Hooke's Law states that the extension is directly proportional to the force applied so:
F/x = constant
F₁/x₁ = F₂/x₂
2 / 0.02 = 1600 / x₂
x₂ = 16 m
Elastic work = 1/2 Fx
= 1/2 * 1600 * 16
= 12.8 kJ
As we sit in a chair, Action force will be only in one direction and that direction would be downward only.
In short, Your Answer would be Option A
Hope this helps!
