Write principle of superposition and explain.

Explanation

Principle of Superposition : "When a particle of medium comes under the influence of two or more waves simultaneously, its net displacement is the vector sum of displacement that would occur under the influence of the individual waves."
When two waves are moving in opposite directions, they possess their nature even after they cross each other.
Though the points which are superposed have different wave pattern then others,
Two equal and opposite waves are superposed that situation is explained in figure and the resultant is zero in (C).