For a particle executing SHM, its kinetic energy, KE=21mω2(A2−x2) ⇒(KE)max=21mω2A2
Potential energy, PE=(PE)max=21mω2A2
Total mechanical energy TE=KE+PE =21mω2A2 ⇒TE=(KE)max=(PE)max
So, if maximum potential energy becomes double, then both total energy and kinetic energy will also become double.
Thus, the statements given in both options (a) and (b) are correct.