Answer
(a) equal to
(b) II
Work Step by Step
(a) It is given that both blocks have the same mass and force constant. Thus, they have equal time period because $T=2\pi \sqrt{\frac{m}{K}}$.
(b) The best explanation is option (II) -- that is, the two blocks experience the same restoring force for a given displacement from equilibrium and hence they have equal periods of oscillation.
