Please help I have been stuck on these homework question for a long time!!

a)

Which of the following best describes the energy and motion of a particle when two waves interfere?The particle vibration is such that equal amounts of energy from each wave are lost but the direction of both is preserved. The particle vibration is such that the energy and direction of each wave is preserved. The particle vibration is such that the energy is preserved for both waves but each wave reverses direction. The particle vibration is such that equal amounts of energy from each wave are lost and both waves reverse direction.Sammy is talking to Sally. Position A is a position in front of Sammy's mouth. Position B is a position in front of Sally's ear. In order for Sally to hear Sammy's voice, air particles must:Bmove from A to B move from A to B and then back to A vibrate perpendicular to a line connecting A and B vibrate parallel to a line connecting A and B