JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<table>
  <thead>
    <tr>
      <th>Number</th>
      <th>Fruits</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td class="num">1</td>
      <td>
        <select class="fruits">
          <option value="1">Apple</option>
          <option value="2">Banana</option>
          <option value="3">Orange</option>
        </select>
      </td>
    </tr>
    <tr>
      <td class="num">2</td>
      <td>
        <select class="fruits">
          <option value=""></option>
          <option value="1">Apple</option>
          <option value="2">Banana</option>
          <option value="3">Orange</option>
        </select>
      </td>
    </tr>
    <tr>
      <td class="num">3</td>
      <td>
        <select class="fruits">
          <option value=""></option>
          <option value="1">Apple</option>
          <option value="2">Banana</option>
          <option value="3">Orange</option>
        </select>
      </td>
    </tr>
     <tr>
      <td class="num">4</td>
      <td>
        <select class="fruits">
          <option value=""></option>
          <option value="1">Apple</option>
          <option value="2">Banana</option>
          <option value="3">Orange</option>
        </select>
      </td>
    </tr>
  </tbody>
</table>
<button onclick= check()>
  Submit
</button>

JavaScript

function check(){
    var $fruits = [];
    $("select.fruits").each(function() {
      var $two = $(this).find("option:selected").text();
      $fruits.push($two)
    })
    for ($i= 1; $i < $fruits.length; $i++) {
    	for ($j= 0; $j < 5; $j++) {
        if ($fruits[$i] == "Apple" && $fruits[$i+$j] == "Banana") {
           alert ("Since you have selected Apple, you cannot select Banana");
          $("select.fruits").val("");
          return false;
        }
        if ($fruits[$i] == "Banana" && $fruits[$i+$j] == "Apple") {
          alert ("Since you have selected Banana, you cannot select Apple");
           $("select.fruits").val("");
          return false;
        }
   	 	}
    }
}