How to make multi level dropdown menu using select option mentod

i want to make multi level dropdown menu using select and option method

<select>
   <option value="" data-display-text="Select">None</option>
   <option value="oranges">SSC</option>
   <option value="oranges">GATE</option>
   <option value="bananas">BANK PO</option>
   <option value="bananas">RAILWAY</option>
 </select>