Step 1: Understanding the Concept
In SHM, acceleration and restoring force are proportional to displacement, \(F=-kx\). Speed and kinetic energy are maximum at the mean position and zero at the extremes.
Step 2: Calculation
From the graph the particle is at the mean position at \(\frac{T}{2}\) and \(T\), and at an extreme position at \(\frac{T}{4}\) and \(\frac{3T}{4}\).
Step 3: Compare the options
At \(T\) the acceleration is zero, so option A fails. At \(\frac{T}{2}\) the speed is maximum, so option C fails. At \(\frac{T}{4}\) the particle is at an extreme where the kinetic energy is zero, so option D fails. At \(\frac{3T}{4}\) the displacement is largest, so the force is maximum (option B).
Final Answer:
The force is maximum at time \(\frac{3T}{4}\).
\[ \boxed{\text{(B) }\text{The force is maximum at time }\dfrac{3T}{4}} \]