Which of the following equations represent an adiabatic process?

(A) Q=0 and ΔE_int = –W
(B) Q=0 and ΔE_int = W
(C) Q=W and ΔE_int = 0
(D) Q=–W and ΔE_int = 0

The answer is: (A) Q=0 and ΔE_int = –W