If a = 60 Cm,b = 80 Cm,Q = −4

If a = 60 cm,b = 80 cm,Q = −4.0 nC,and q = 1.5 nC,what is the magnitude of the electric field at point P?

A) 68 N/C
B) 72 N/C
C) 77 N/C
D) 82 N/C
E) 120 N/C