JSFiddle - React, Tailwind, and code Playground

HTML

<div class="adult-sizes-box">
	<h2 class="section-title">3. Design Location & Colors</h2>
	<p class="ptext">You can select maximum 4 locations per shirt and Each location can have a maximum 4 colors. The base price includes the First Location and One color</p>
	<div class="pc-row location-1">
	<div class="locations-colors pc-col quote-sizes">
	  <h4>Choose location below</h4>
	   <label for="location_one"><span>Location</span>
	    <select name="location_one" id="location_one" class="linked-drop-down">
         <option value="">choose location</option>
		 <option value="Full_Chest">Full Chest</option>
		 <option value="Full_Back">Full Back</option>
         <option value="Front_Left_Chest">Front Left Chest</option>
         <option value="Front_Right_Chest">Front Right Chest</option>
         <option value="Left_Sleeve">Left Sleeve</option>
		 <option value="Right_Sleeve">Right Sleeve</option>		 
        </select></label>
		
	</div>
	</div>
	<div class="pc-row location-2">
		<div class="locations-colors pc-col quote-sizes">
	   <label for="location_two"><span>Location</span>
	    <select name="location_two" id="location_two" class="linked-drop-down">
         <option value="">choose location</option>
		 <option value="Full_Chest">Full Chest</option>
		 <option value="Full_Back">Full Back</option>
         <option value="Front_Left_Chest">Front Left Chest</option>
         <option value="Front_Right_Chest">Front Right Chest</option>
         <option value="Left_Sleeve">Left Sleeve</option>
		 <option value="Right_Sleeve">Right Sleeve</option>		 
        </select></label>
		
	</div>
	</div>
		<div class="pc-row location-3">
		<div class="locations-colors pc-col quote-sizes">
	   <label for="location_three"><span>Location</span>
	    <select name="location_three" id="location_three" class="linked-drop-down">
         <option value="">choose location</option>
		 <option value="Full_Chest">Full Chest</option>
		 <option value="Full_Back">Full Back</option>
        ...

CSS

.pc-row {width: 100%; display: table; table-layout: fixed; }.pc-col {display:table-cell;vertical-align:top}
.location-2,.location-3,.location-4{display:none}.quote-sizes select{border:1px solid #ccc;font-size:14px;height:30px;padding:0 5px}
.quote-sizes label {cursor:inherit;display:block;width:100%;overflow:hidden;white-space:nowrap;margin-bottom:10px}.quote-sizes label span{font-size:14px;text-align:right;float:left;margin-right:3px;vertical-align:middle;width:120px}
#add-location,#rm-location{margin:20px 0;width:160px;float:left}#add-location a,#rm-location a{text-decoration:none;color:#000;border:2px solid #990000;font-size:13px;padding:5px}

JavaScript

var i = 2;
$(".addonemore").click(function(){
    console.log(i);
    if( i > 4){
        alert("You can add only a maximum of 4 locations");
    } else {
        $('.location-'+i).css({'display':'table'});
        i++;
    }
});
$(".rmone").click(function(){
    console.log(i);
    if( i <= 2){
        alert("You need at least one location and color");
    } else {
        $('.location-'+(i-1)).css({'display':'none'});
        i--;
    }
});