Answer:
C) 1 s
Step-by-step explanation:
The period of a mass-spring system is given by the formula:

where
m is the mass hanging on the spring
k is the spring constant
As we can see from the equation above, the period of the system does NOT depend on the initial amplitude of the oscillation. Therefore, even if the initial amplitude is changed from 5 cm to 10 cm, the period of the system will remain the same, 1 s.