At the center, 6 unmarked red balls are interspersed with 4 blue balls marked with plus signs. A green cloud with 2 concentric white lines surrounds the center, with 2 small green balls marked with minus signs on the inner white line and 2 small green balls marked with minus signs on the outer white line. How many neutrons does this atom have? 4 6 10 14

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 another, their amplitudes adds up