|Que.||Which of the following are not regular?
(A) Strings of even number of a’s.
(B) Strings of a’s, whose length is a prime number.
(C) Set of all palindromes made up of a’s and b’s.
(D) Strings of a’s whose length is a perfect square.
|a.||(A) and (B) only|
|b.||(A), (B) and (C) only|
|c.||(B), (C) and (D) only|
|d.||(B) and (D) only|
|Answer:(B), (C) and (D) only|