Answer:
Correct answer is constructive interference (When the trough of one light wave meets the trough of a second light wave, constructive interference occurs. )
Step-by-step explanation:
When two light waves(component waves) of nearly equal wavelength superpose that time a resultant wave is formed. This resultant wave can have equal amplitude, greater amplitude or lower amplitude than the component waves. This phenomena is known as interference.
There are two types of interference
Constructive interference
When two light wave superpose in same phase it means when the trough of one light wave meets the trough of a second light wave and crest of one light wave meets the crest of a second light wave that time a resultant wave of greater amplitude is formed. This phenomena is known as constructive interference.
Destructive interference:
When two light wave superpose in opposite phase it means when the trough of one light wave meets the crest of other light wave that time a resultant wave of lower amplitude is formed and this phenomena is known as destructive interference.