Contour lines are lines that signifies the elevation on a mountain or hill
The equation for work (W) done by an electric field is:
W = qΔV
where q is the magnitude of the charge and ΔV is the potential difference. The question gives you W and q, so plug n' play to find ΔV:
10 = 2ΔV
ΔV = 5
It's either staying there or is going at the same pace