A 0.80kg block attached to an ideal spring moves along a horizontal frictionless surface. The block passes through x1=0.10m with speed 1.2m⋅s−1 and later passes through x2=0.20m with speed 0.80m⋅s−1. What is the amplitude of the oscillation?
a) 0.21m
b) 0.30m
c) 0.25m
d) 0.19m