Answer:
"Wave 3 resulted from constructive interference and Wave 4 resulted from destructive interference."
Step-by-step explanation:
Constructive Interference:
When two waves meet in such a way that their crests line up together, then it's called constructive interference. The resulting wave has a higher amplitude.
Destructive Interference:
In destructive interference, the crest of one wave meets the trough of another, and the result is a lower total amplitude.
The amplitude of Wave 3 is higher than both the Waves, 1 & 2, so it must be a result of constructive interference.
The amplitude of Wave 4 is less than both the Waves, 1 & 2, so it must be a result of destructive interference.