The overall efficiency of steam locomotive is around_____________?
A. 5 to 10 percent
B. 15 to 20 percent
C. 25 to 35 percent
D. 35 to 45 percent
A. 5 to 10 percent
B. 15 to 20 percent
C. 25 to 35 percent
D. 35 to 45 percent