CategoryId  UserId  CategoryName    tipo
  73            1   Salario         10
  74            1   Comisiones      10
  75            1   Horas extra     12
  76            1   Bono            10
  77            2   Salario         10
  78            2   Comisiones      10
  79            2   Horas extra     12
  80            2   Bono            10

$conexion = mysqli_connect("localhost", "root", "pass", "mi_base");

 $query = "select distinct category.CategoryId, category.CategoryName from
 category where tipo = 10";
 $mResult = mysqli_query($conexion,$query);

<select name="ecategory" class="form-control">
                                   <?php while($col =
                                    mysqli_fetch_assoc($mResult )){ ?>
                       <option value="<?php echo $col['CategoryId'];?>">
                                   <?php echo $col['CategoryName'];?>
                      </option>
                                 <?php } ?>
                     </select>
               </div>