On Bootstrap 4.0, we have to declare the table rows as flex-boxes by adding class d-flex, and also drop xs, md, suffixes to allow Bootstrap to automatically derive it from the viewport.
So it will look following:
<table class="table">
<thead>
<tr class="d-flex">
<th class="col-2"> Student No. </th>
<th class="col-7"> Description </th>
<th class="col-3"> Amount </th>
</tr>
</thead>
<tbody>
<tr class="d-flex">
<td class="col-2">test</td>
<td class="col-7">Name here</td>
<td class="col-3">Amount Here </td>
</tr>
</tbody>
</table>
Hope this will be helpful to someone else out there!
Cheers!