The correct answer to the question is : B which represents the amplitude of the motion.
EXPLANATION:
As per the question, the graph is plotted between displacement versus time .
The motion of the mass attached to the spring is simple harmonic in nature.
We are asked to denote the arrow representing the amplitude of the motion.
The amplitude of the motion is defined as the maximum displacement of the mass from its equilibrium or mean position.
As per the diagram, the maximum displacement of the mass is denoted by arrow B.
Hence, the answer of the question is B which gives the amplitude of the motion.
