JSFiddle - React, Tailwind, and code Playground

HTML

<div id="featured_1">
    <div class="product-options">
        <h2>Product title</h2>
        <div class="product-option">
            <select class="product-option-value">
                <option>Test</option>
                <option>Another Test</option>
            </select>
        </div>
    </div>
</div>

CSS

#featured_1 .product-options .product-option:nth-child(2) .product-option-value option:nth-child(1) {background:red}

#featured_1 .product-options .product-option:nth-child(2) .product-option-value option:nth-child(2) {background:green}

JavaScript

$("#featured_1 .product-option-value").change(function(){
    if (this.selectedIndex == 0) {
        $("body").css("background-color", "red");
    } else {
        $("body").css("background-color", "green");
    }
});