Given the rationale, provide a reasonable question and answer. Step-by-step reasoning process: S = (500 + 300)/45 = 800/45 * 18/5 = 64
 The question and answer:
A train 500 meters long completely crosses a 300 meters long bridge in 45 seconds. What is the speed of the train is?
Options:
(A) 32
(B) 28
(C) 49
(D) 64
(E) 21
The answer is (D)