A long Rail (approximately 700 meters) made up of steel is struck to produce a sound. The person standing on the other end of the rail would hear in which among the following pattern?

• A. He listens the sound waves once propagated via steel
• B. He listens the sound waves once propagated via air
• C. He listens the sound waves twice, first propagated via steel and second propagated via air
• D. He listens the sound waves twice, first propagated via air and second propagated via steel