The difference in the Potential energies between two arbitrary positions downward displacements X1 and X2. (X2 > X1)

A

$$\frac{1}{2}k[x1 - x2]^2$$

B

$$\frac{1}{2}k[(x2)^2 - (x1)^2]$$

C

$$\frac{1}{2}k[(x1)^2 - (x2)^2]$$

D

$$\frac{1}{2}k[x1 - x2]$$