A worker was working on the rail track. A boy at a distance holds his ear near the rail track. This boy was able to hear sound of the blow of workman twice. It is because of

A. The speed of sound is greater in steel than in air

B. The speed of sound is greater in air than in steel

C. Part of the sound wave is reflected between the rail tracks

D. His ears are at different distance from the source

Answer: Option A