Answer:
A. Constructive
B. Destructive
C. Destructive
D. Constructive
Step-by-step explanation:
Constructive interference takes place at locations along the path of two superposed waves where the waves are in phase such that a high or low point of one of the waves corresponds with a high or low point of the other wave which gives a resulting wave amplitude which is the sum of the amplitudes of the individual waves
Destructive interference takes place at locations along the path of two superposed waves where one wave is out of phase with the other wave such that a high or low point of one of the waves coincides with a low or high point of the other wave respectively thereby cancelling the effect of the other wave and giving a resulting wave that has an amplitude which is the difference in the amplitudes of the individual waves
Therefore;
At point A, the peak of each wave partially coincides resulting in constructive interference
At point B, the peak of the blue wave and the trough of the red wave partially coincides resulting in destructive interference
At point C, the through of the blue wave and the peak of the back wave partially coincides resulting in destructive interference
At point D, the trough of each wave partially coincides resulting in constructive interference.