In the rectangle of the above figure, the sides have lengths 5.0 cm and 15 cm, q₁ = -5.0 μC, and q₂ = +2.0 μC. With V=0 at infinity, What is the electric potential at (a) corner A and (b) corner B? (c) How much work is required to move a charge q₃ = +3.0 μC from B to A along a diagonal of the rectangle?