Tessellate S.T.E.M.S. (2019) - Computer Science - College - Set 2 - Objective Problem 1

Below are three different abstract machines. Which of the three do not accept the same class of languages as that of regular language?

• A) A two way finite state automaton is like an usual finite state automaton, except that the input is given on a tape which is read by a head, and the transitions may ask to move the head to the left or right besides choosing the next state.
• B) An alternating finite state automaton is an automaton which has universal states besides non-deterministic states. When the run of the automaton reaches an universal state, the run is said to succeed if the continuation of the run through all of its successors succeed. (Contrast with an non-deterministic state, where the continuation through any one successor is good enough.)
• C) Consider a single tape Turing machine which has the additional restriction that the part of the tape on which the input was written cannot be overwritten.

This problem is a part of Tessellate S.T.E.M.S (2019)