To solve this problem, we need to understand the relationship between displacement and acceleration in simple harmonic motion (SHM).$\\$In SHM, the displacement $x$ of a particle can be described by the equation:$\\ x = A \cos(\omega t + \phi) \\$where:$\\$• $A$ is the amplitude,$\\$• $\omega$ is the angular frequency, and$\\$• $\phi$ is the phase constant.$\\$The acceleration $a$ of the particle is given by:$\\ a = -\omega^2 x \\$Substituting the expression for $x$ into the equation for $a: \\ a = -\omega^2 A \cos(\omega t + \phi) \\$This can be rewritten as:$\\ a = A \omega^2 \cos(\omega t + \phi + \pi) \\$This shows that the acceleration is $\pi$ radians out of phase with the displacement.$\\$Therefore, the phase difference between displacement and acceleration in SHM is $\pi$ radians.$\\$This corresponds to Option 4.