The correct answer should be C. Seismic vibrations cause the ground to act like a liquid. This is easily testable and you can even do it in your own house. If you shake a jar full of sand and simulate seismic vibrations like an earthquake, you will see that the ground in a jar or sand or anything similar will behave more like liquid than like solids.
Soil liquefaction occurs when A. seismic vibrations have no impact on topsoil. B. seismic vibrations pollute the entire atmosphere. C. seismic vibrations cause the ground to act like a liquid. D. seismic vibrations impact only the inner core of Earth.