People have been able to make an object exceed the speed of light.

True
False

False...

But light is made up of particles called photons. ... "As objects travel faster and faster, they get heavier and heavier – the heavier they get, the harder it is to achieve acceleration, so you never get to the speed of light," says Roger Rassool, a physicist at the University of Melbourne, Australia.

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."