If the potential energy between two molecules is given by `U= -(A)/(r^6) + B/(r^(12))` , then at equilibrium , separation between molecules , and the potential energy are :

Options

A. `((B)/(2A))^(1/6) , - (A^2)/(2B)`
B. `((B)/(2A))^(1/6) ,0`
C. `((2B)/(A))^(1/6) , - (A^2)/(4B)`
D. `((2B)/(A))^(1/6) , - (A^2)/(2B)`