8. The electric potential at a point in a XY plane is given by V= (6.0 V/m2) x2 - (5.0 V/m2) y'. In unitvector notation, what is the electric field at the point ( 6.0m, 4.0.m)? A. -72 i + 40 j V/m B. 40 i - 72 j V/m C. -12 i + 12 j V/m D. -36 i - 20 j V/m E. 72 i - 40 j V/m