Answer:
B. The stiffer the spring, the greater the force required to restore its position.
Explanation:
The 'restoring force' (the force required to restore the position of a spring) is given by:

where
F is the restoring force
k is the spring constant, which determines its stiffness (the higher the value of k, the stiffer the spring)
x is the displacement of the spring relative to its natural length
From the formula, we see that the higher the value of k (so, the stiffer the spring), the larger the restoring force, so the correct option is
B. The stiffer the spring, the greater the force required to restore its position