Can I take out the last page in the UPSC Mains answer sheet as a?
No and you should never do that. Please do not ever do that. Answer booklets are consecutively page numbered including rough sheets and the total number of pages are indicated on the front instructions sheet. So if you ever pull out any page or if any page is missing, your question booklet will not be evaluated. Hence, sincerely do not try that unless it is your death wish. Cheers! Peace out!!