Which statement best describes the superposition principle?
A. If two in-phase waves arrive simultaneously at a point, their amplitudes add up.
B. If two out-of-phase waves arrive simultaneously at a point, their amplitudes add up.
C. If two in-phase waves arrive at a point one after another, their amplitudes add up.
D. If two out-of-phase waves arrive at a point one after the other, their amplitudes adds up