Analyzing graphs of spring-mass systems

Two blocks connected to identical ideal springs are oscillating on a horizontal frictionless surface. The motion of the blocks

A

and

B

over time are shown in the graph below.

Why are the periods different for blocks $A$ ‍ and $B$ ‍?

(Choice A)
Block $B$ ‍ has a shorter period because its smaller amplitude means the spring constant is bigger.
(Choice B)
Block $A$ ‍ has a longer period because it has more mass.
(Choice C)
Block $A$ ‍ has a longer period because it has a larger amplitude.
(Choice D)
Block $B$ ‍ has a longer period because it has more mass.

Class 11 Physics (India) - Hindi