sugars

var result = [];

$('.m-s-3').each(function(index) {
  result.push($(this).find('td').eq(2).text().trim());
});

console.log(result);

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<table>
  <tbody>
    <tr class="m-s-3">
      <td>A</td>
      <td>B</td>
      <td>20</td>
      <td>D</td>
    </tr>
    <tr class="m-s-3">
      <td>A</td>
      <td>B</td>
      <td>
        <span>44</span>
      </td>
      <td>D</td>
    </tr>
    <tr class="m-s-3">
      <td>A</td>
      <td>B</td>
      <td>55</td>
      <td>D</td>
    </tr>
  </tbody>
</table>