In the presence of an electrostatic field, you find that you must do positive work on an electron to move it from point \(A\) to point \(B\) without changing its kinetic energy.

(a) Considering just the electron as our system, has the system's electric potential energy increased, decreased, or remained the same?

(b) What if your system consists of both the electron and the charged particles that are the source of the electrostatic field?

(c) Is the electrostatic potential difference between A and B positive, negative, or zero?