How long would it take for a sound impulse to travel through a copper rod 2.0 km long?
s
0.057
0.57
1.75
17.5

It would take roughly half a second so base that off your answers and you could get the right answer 

hope that helped

At standard temperature, shear force propagation occurs at 3570 meters per second. Thus for a copper rod (assumed at ST) measuring 2 km, an impulse would cross its length in 2/3.57 = .56022409 seconds— thus approximately .57 seconds.

Iagree c would be the answer