What is the conjugate?

Question

What is the conjugate of -2+√b ?

(A) -2 - √b

(B) (1)/(-2 + √b)

(C) b + 4

(D) 2 + √b

(E) none of the above

For this I got (E) none of the above, because I got -2√b. Is this correct?

Answer 1

The conjugate of an expression like a+√b is a-√b. Answer (A) is correct.

Answer 2

No, the answer is A.

(-2+√b)(-2-√b) = 4-b