The potential energy function for the force between two in a diatomic molecule can approximately be expressed as `U(x)=(a)/(x^(12))-(b)/(x^(4))`, where `a` and `b` are positive constants, and `x` is the distance between the atoms. Answer the following question by selecting most appropriate alternative.
The dissociation energy of the molecule is (initially molecule is at rest at equilibrium)

Options

A. `-(b^(2))/(4a)`
B. `-(b^(2))/(2a)`
C. `+(b^(2))/(4a)`
D. `+(b^(2))/(2a)`