variable.php

<?php
/**
 * Variable product add to cart
 *
 * @author  WooThemes
 * @package WooCommerce/Templates
 * @version 2.4.0
 */
if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

global $product;

$attribute_keys = array_keys( $attributes );

do_action( 'woocommerce_before_add_to_cart_form' ); ?>

<form class="variations_form cart" method="post" enctype='multipart/form-data' data-product_id="<?php echo absint( $product->id ); ?>" data-product_variations="<?php echo esc_attr( json_encode( $available_variations ) ) ?>">
    <?php do_action( 'woocommerce_before_variations_form' ); ?>

    <?php if ( empty( $available_variations ) && false !== $available_variations ) : ?>
        <p class="stock out-of-stock"><?php _e( 'This product is currently out of stock and unavailable.', 'woocommerce' ); ?></p>
    <?php else : ?>
        <table class="variations" cellspacing="0">
            <tbody>
                <?php
                    $variations_arr = array();
                    foreach ( $attributes as $attribute_name => $options ) :
                        ob_start(); ?>
                        <tr>
                            <td class="label"><label for="<?php echo sanitize_title( $attribute_name ); ?>"><?php echo wc_attribute_label( $attribute_name ); ?></label></td>
                            <td class="value">
                                <?php $selected = isset( $_REQUEST[ 'attribute_' . sanitize_title( $attribute_name ) ] ) ? wc_clean( $_REQUEST[ 'attribute_' . sanitize_title( $attribute_name ) ] ) : $product->get_variation_default_attribute( $attribute_name );
                                wc_dropdown_variation_attribute_options( array( 'options' => $options, 'attribute' => $attribute_name, 'product' => $product, 'selected' => $selected ) );
                                echo end( $attribute_keys ) === $attribute_name ? '<a class="reset_variations" href="#">' . __( 'Clear selection', 'woocommerce' ) . '</a>' : ''; ?>
                            </td>
                        </tr>
                        <?php $variations_ob = ob_get_clean();
                        $variations_arr[wc_attribute_label($attribute_name)] = $variations_ob;
                    endforeach;

                    foreach ($variations_arr as $name => $ob) {
                        echo str_ireplace('choose an option', 'Choose '.$name, $ob );
                    } ?>
                <?php endforeach;?>
            </tbody>
        </table>

        <?php do_action( 'woocommerce_before_add_to_cart_button' ); ?>

        <div class="single_variation_wrap" style="display:none;">
            <?php
                /**
                 * woocommerce_before_single_variation Hook
                 */
                do_action( 'woocommerce_before_single_variation' );

                /**
                 * woocommerce_single_variation hook. Used to output the cart button and placeholder for variation data.
                 * @since 2.4.0
                 * @hooked woocommerce_single_variation - 10 Empty div for variation data.
                 * @hooked woocommerce_single_variation_add_to_cart_button - 20 Qty and cart button.
                 */
                do_action( 'woocommerce_single_variation' );

                /**
                 * woocommerce_after_single_variation Hook
                 */
                do_action( 'woocommerce_after_single_variation' );
            ?>
        </div>

        <?php do_action( 'woocommerce_after_add_to_cart_button' ); ?>
    <?php endif; ?>

    <?php do_action( 'woocommerce_after_variations_form' ); ?>
</form>

<?php do_action( 'woocommerce_after_add_to_cart_form' ); ?>