Q. 28 Consider the following types of languages:
L1 Regular, L2: Context-free, L3: Recursive, L4: Recursively enumerable.
Which of the following is/are TRUE?
I. L3' U L4 is recursively enumerable II. L2 U L3 is recursive III. L1* U L2 is context-free IV. L1 U L2' is context-free
(A) I only
(B) I and III only
(C) I and IV only
(D) I, II and III only
Answer: (D)
Explanation:
