Answer:
Speed of sound wave v=νλ=2000×0.35=700 m/s
Distance d=1.5 km=1500 m
Time t=vd=7001500≈2 s
Mark out the ones it can’t possibly be which will leave you with 2 left! After possibly go back in notes and see if they talked about it! Sorry it’s not much help but it makes it easy because I can’t figure out the answer!:(
<span>Fall of the Roman Empire.</span>