Why won't shirt sizes pop up?

<?php
$products = array();

$products[101] = array(
    "name" => "Logo Shirt, Red",
    "img" => "img/shirts/shirt-101.jpg",
    "price" => 18, 
    "paypal" => "P92T46BGE6Z5Q",
    "sizes" => array("Small","Medium","Large","X-Large");
);

$products[102] = array(
    "name" => "Mike the Frog Shirt, Black",
    "img" => "img/shirts/shirt-102.jpg",
    "price" => 20,
    "paypal" => "ZV3388WCHG7CN",
    "sizes" => array("Small","Medium","Large","X-Large");
);

$products[103] = array(
    "name" => "Mike the Frog Shirt, Blue",
    "img" => "img/shirts/shirt-103.jpg",    
    "price" => 20,
    "paypal" => "73T4U4ESTFCGW",
    "sizes" => array("Small","Medium","Large","X-Large");
);

$products[104] = array(
    "name" => "Logo Shirt, Green",
    "img" => "img/shirts/shirt-104.jpg",    
    "price" => 18,
    "paypal" => "QP3T8RJ2JGLJ6",
    "sizes" => array("Small","Medium","Large","X-Large");
);

$products[105] = array(
    "name" => "Mike the Frog Shirt, Yellow",
    "img" => "img/shirts/shirt-105.jpg",    
    "price" => 25,
    "paypal" => "JPNA6HQS4R6AC",
    "sizes" => array("Small","Medium","Large","X-Large");
);

$products[106] = array(
    "name" => "Logo Shirt, Gray",
    "img" => "img/shirts/shirt-106.jpg",    
    "price" => 20,
    "paypal" => "9U8XDFY7PCVYW",
    "sizes" => array("Small","Medium","Large","X-Large");
);

$products[107] = array(
    "name" => "Logo Shirt, Turquoise",
    "img" => "img/shirts/shirt-107.jpg",    
    "price" => 20,
    "paypal" => "BK6EVECGZ78XG",
    "sizes" => array("Small","Medium","Large","X-Large");
);

$products[108] = array(
    "name" => "Logo Shirt, Orange",
    "img" => "img/shirts/shirt-108.jpg",    
    "price" => 25,
    "paypal" => "886DTRMT4K7UC",
    "sizes" => array("Large","X-Large");
);

?>

<?php 
include ('INC/products.php'); 

if (isset($_GET["id"])) {

    $product_id = $_GET["id"];

    if (isset($products[$product_id])) {

        $product = $products[$product_id];

    }

} 

if (!isset($product)) {

    header("Location: shirts.php");

    exit();

}

$section = "shirts";
$pageTitle = $product["name"];

include ("INC/header.php");

?>

    <div class="section page">

        <div class="wrapper">

            <div class="breadcrumb">

                <a href="shirts.php"> Shirts </a> &gt;

                <?php echo $product["name"]; ?>

            </div>

            <div class="shirt-picture">

                <span>

                    <img src="<?php echo $product["img"]; ?>" alt="<?php echo $product["name"]; ?>">

                </span>

            </div>

            <div class="shirt-details">

                <h1> 

                    <span class="price"> $

                        <?php echo $product["price"]; ?>

                    </span>

                         <?php echo $product["name"]; ?> 

                </h1>

                <form target="paypal" action="https://www.paypal.com/cgi-bin/webscr" method="post">

                    <input type="hidden" name="cmd" value="_s-xclick">

                    <input type="hidden" name="hosted_button_id" value="<?php echo $product["paypal"]?>">

                    <input type="hidden" name="item_name" value="<?php echo $product["name"]?>">

                        <table>

                            <tr>

                                <th> 

                                    <input type="hidden" name="on0" value="Size"> 

                                    <label for="os0"> Size </label> 

                                </th>

                                <td> 

                                    <select name="os0" id="os0">

                                         <?php foreach($product["sizes"] as $size) { ?>

                                             <option value="<?php echo $size; ?>"><?php echo $size; ?> </option>

                                         <?php } ?>

                                    </select> 

                                </td>

                            </tr>

                        </table>

                    <input type="submit" value="Add To Cart" name="submit">

                </form>

                <p class="note-designer"> *All Shirts Are Designed By Mike The Frog. </p>

            </div>

        </div>

    </div>

<?php include ("INC/footer.php"); ?>