$colorProductId = array('2' => 'Black','3' => 'Blue');

    <span class="select_span">Select Color: </span>
                                        <select id="color_drop_down_options" data-role="color_drop_down_options" class="color_drop_down_options" onChange="check();">
                                            <?php foreach($colorProductId as $key => $value): ?>
                                                <option value="<?php /* @escapeNotVerified */ echo $value ?>"<?php if ($value): ?> selected="selected"<?php endif ?>>
                                                    <?php /* @escapeNotVerified */ echo $key ?>
                                                </option>
                                            <?php endforeach; ?>
                                        </select>