Three Carnot Engines Operate Between Temperature Reservoirs as Follows: Engine

Multiple Choice

Three Carnot engines operate between temperature reservoirs as follows: Engine A: T_h = 1,100 K,T_c = 1,000 K;Engine B: T_h = 1,100 K,T_c = 500 K;Engine C: T_h = 550 K,T_c = 500 K.Which two engines have the same thermal efficiency?
​

A) A and B
B) B and C
C) A and C
D) No two have the same thermal efficiency.
E) ​A and B and C