Which situations might cause two observes (A and B) to measure different frequencies for the same vibrating object? Select the two correct answers

Question

Observer A and Observer B are the both stationary and at the same distance from the object

Observer A and B are stationary but at different distances from the vibrating object

Observer A and observer B are moving at diffrent speeds relative to each other

Observer A stationary and Observer B is moving

Answer 1

Observer A and B are stationary but at different distances from the vibrating object

Observer A and observer B are moving at different speeds relative to each other