Hey,,,, There is no special way to write questions no. in professional exams... It is same as u write them in any other academic exams,,.... but YeS u have to be careful while writing sub questions number along with main question number...
Again it would be better if u write question no in the top of the sheet as suggested by the Company secretaryship postal test papers guidelines..... e.g.
ANSWER TO Q. NO. 1
(a)
(b)..
& so on....
Thanks & Regards
Nishant Saurabh