Hence, it depends on the sender and receiver how they agree for bit stuffing after all it's a synchronization mechanism. We cannot say in real world environment that according to one book it must be this or that. Results must be general.
So, as long as sender and receiver are agreeing on the framing policy, no problem would come.
Also, in GATE I have never seen such questions where there would be ambiguity in deciding answer in these types of questions. If ever they will come, they may come under multi-statement true type questions.
Hence forouzan is also correct :)