This was supposed to be put in the "physics" section, but after submitting it into "chemistry" I was unable to change it

Let's say that there are two opposite charges of equal magnitude attached to either end of a spring. The two charges cause the spring to contract and reach a new equilibrium. If I wanted to know the spring constant of the spring and I knew the original length of the spring and the contracted length of the spring, as well as the charges on each end, would I:

A) Use the distance between the charges (the spring length) BEFORE contraction to get the spring force (using coulomb's law) and divide that by the distance that it contracted to get the spring constant OR

B) Use the distance between the charges (the spring length) AFTER contraction to get the spring force (using coulomb's law) and divide that by the distance that it contracted to get the spring constant

Cramster used option A to solve this type of problem, but I could have SWORN that option B is the correct approach.