If the potential energy between two molecules is given by U = - A/r₆+ B/r₁₂, then at equilibrium, the separation between molecules, and the potential energy are:

A. [2B / A]⅙, [-A² / 4B]
B. [2B / A]⅙, [-A² / 2B]
C. (B / A)⅙, 0
D. (B / 2A)⅙, [-A² / 4B]