An insect at rest on the water surface produces circular ripples using its legs, as shown in diagram 1. The insect then starts moving to the right, as shown in diagram 2. Which row describes how the movement of the insect changes the waves at $X$?
- Afrequency decreases, wave speed increases
- Bfrequency decreases, wave speed stays the same
- Cfrequency increases, wave speed increases
- Dfrequency increases, wave speed stays the same