How Much Work Must We Do on an Electron to Move

How much work must we do on an electron to move it from point $A$ , which is at a potential of $+ 50 \mathrm {~V}$ , to point $\mathrm { B }$ , which is at a potential of $- 50 \mathrm {~V}$ , along the semicircular path shown in the figure? Assume the system is isolated from outside forces. $\left( e = 1.60 \times 10 ^ { - 19 } \mathrm { C } \right)$

A) $1.60 \times 10 ^ { - 17 } \mathrm {~J}$
B) $- 1.60 \times 10 ^ { - 17 } \mathrm {~J}$
C) $1.6 \mathrm {~J}$
D) $- 1.6 \mathrm {~J}$
E) This cannot be determined because we do not know the distance traveled.