Many might have marked B,but one must be able to rigorously prove it:
Why is 4 false?
Here we must know what m is.Multiplication can only be performed if we know one of its operands.There is no bound on m, and since you cannot count till infinity(counting requires a distinct state for each increment) and you cannot have infinite states counting is not possible.This can be done with the help of LBA
Why is 2 true?
We'll decompose the problem into 2 parts as we don't have to be deterministic.
Case 1:
m-n = p-q .Do,simple push and pop for 'a' and 'b' respectively.Now,if 'b' is one the stack terminate . else do the similar operation for 'c' and 'd' .Now compare the leftover 'a' with leftover 'c',this is again trivial.
Case 2: n-m = p-q can be done similarly.
Answer:b)