Answer:
D). Destructive
Step-by-step explanation:
When two waves of same frequency superimpose at a point on the string in then the resultant phenomenon is known as interference of wave.
Here we know that interference of two waves is of two types
1) Constructive interference
When two waves superimpose in same phase then the resultant of two waves superposition is maximum in amplitude and intensity. This phenomenon is known as constructive interference and here the direction or phase must be same.
2) Destructive interference
When two waves superimpose in opposite phase then the resultant of two waves superposition is minimum in amplitude and intensity. This phenomenon is known as destructive interference and here the direction or phase must be opposite.
Since in the given situation the two particles are in opposite phase so here the resultant interference is destructive interference