Three Infinite Planes of Charge, A, B and C, Are

Multiple Choice

Three infinite planes of charge, A, B and C, are vertical and parallel to one another.There is a uniform electric field to the left of plane A and a uniform electric field to the right of plane C.The field points to the left and the field points to the right.The signs of the charges on plates A, B and C may be:

A) (-, -, -.)
B) +, -, -.
C) +, -, +.
D) +, +, +.
E) any one of the above.