Question

a charges of +2c and -2c are situated at points p and q respectively which are at a distance apart. a point x is mid-way between p and q. which of the following correctly describes the electric field and the electric potential at point x?

Answer 1

Where is "the following"?
Fields add, so do potentials
Anyway
E1 = k q1 / r^2
E2 = k q2 / r^2

q is charge and r is distance from charge to point of interest
V1 = -k q1 / r
V2 = -k q2 / r

V is potential and r will be x, the distance

Answer 2

Note that by examining the equations @douglaswinslowcooper posted, you can get the correct answer without doing a single calculation.