GATE | GATE-CS-2002 | Question 39

Which of the following is true?
(A) The complement of a recursive language is recursive.
(B) The complement of a recursively enumerable language is recursively enumerable.
(C) The complement of a recursive language is either recursive or recursively enumerable.
(D) The complement of a context-free language is context-free.

Answer: (A)
Explanation: See http://en.wikipedia.org/wiki/Recursive_language#Closure_properties
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