b is the correct answer since if L2 is regular then A(L) is regular (if L is regular or not regular; like in question 9, i prove it by using Myhill-Nerode Theorem.) and if L2 is CFL then like the example above, its not close under this operation.

c is not correct since we prove in question 9 that it is close for L2 regular

d is not correct since b is correct :-)

Note: A(L) from question 9 is A(L2) in question 10 and A(L) from question 10 is A(L2) in question 9.

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