Wordpress - 订阅所有内容：将单选按钮转换为下拉菜单

How to convert this list of options from radio buttons to a dropdown menu? Below is code pulled from the single-product.php template.

<div class="wcsatt-options-wrapper" <?php echo count( $options ) === 1 ? 'style="display:none;"' : '' ?>><?php

if ( $prompt ) {
    echo $prompt;
} else {
    ?><h3><?php
        _e( 'Choose a subscription plan:', WCS_ATT::TEXT_DOMAIN );
    ?></h3><?php
}

?><ul class="wcsatt-options-product"><?php
    foreach ( $options as $option_id => $option ) {
        ?><li class="<?php echo $option_id !== '0' ? 'subscription-option' : 'one-time-option'; ?>">
            <label>
                <input type="radio" name="convert_to_sub_<?php echo $product->id; ?>" data-custom_data="<?php echo esc_attr( json_encode( $option[ 'data' ] ) ); ?>" value="<?php echo $option_id; ?>" <?php checked( $option[ 'selected' ], true, true ); ?> />
                <?php echo $option[ 'description' ]; ?>
            </label>
        </li><?php
    }
?></ul>

I got this to work! However, I'm pretty sure that I'm not supposed to use the checked parameter with a dropdown menu... Any suggestions for improvement?

<ul class="wcsatt-options-product">
    <select name="convert_to_sub_<?php echo $product->id; ?>" data-custom_data="<?php echo esc_attr( json_encode( $option[ 'data' ] ) ); ?>">
    <?php
        foreach ( $options as $option_id => $option ) {
            ?><li class="<?php echo $option_id !== '0' ? 'subscription-option' : 'one-time-option'; ?>">
                <label>
                    <option value="<?php echo $option_id; ?>" <?php checked( $option[ 'selected' ], true, true ); ?>> <?php echo $option[ 'description' ]; ?> </option>
                </label>
            </li><?php
        }
    ?>
    </select>
</ul>

I don't know what system you are using or how the validation or anything works, but something like this would get you close if not there:

 <ul class="wcsatt-options-product">
    <select name="convert_to_sub_<?php echo $product->id; ?>">
<?php
    foreach ( $options as $option_id => $option ) {
        ?><li class="<?php echo $option_id !== '0' ? 'subscription-option' : 'one-time-option'; ?>">
            <option value="<?php echo $option_id; ?>" data-custom_data="<?php echo esc_attr( json_encode( $option[ 'data' ] ) ); ?>" <?php echo($option[ 'selected' ] ? ' selected="selected" : '' ?>><?php echo $option[ 'description' ]; ?></option>                    
        </li><?php
    }
?></select></ul>

Essentially you are just converting the input elements to <option>'s and wrapping it all in <select> tags.