Are we allowed to ask questions about the old Exams?
If it is so, in regard to the old Exam, I have checked out Question 6 and for the second question, I am not a hundred percent sure how to answer it.
Computing the Table in the previous question, I would believe that after processing "mumb" as C("mmaym", "mumb") > 1 the next processed sequence would be "mumm", as Push("mu", "b", "m") would be the last push on the stack. And "m" is the next letter in the lexicographic ordering.