Answer A is correct.
Imagine a fixed negatively charged particle at the focus of the electric field lines. The electric force is a central force. The free positively charged particle orbits in a circle around the fixed negative charge. There are other electric field lines apart from those shown, and only part of the circular path is shown.
A circular path is not the only possibility in a central force field. Parabolic and hyperbolic paths are also possible, as well as straight-line paths heading directly towards or away from the fixed charge. These paths look very nearly circular at the vertex, but further away they get straighter and straighter. The whole path is not circular.
Answer B would be possible if there is another force acting on the positively charged particle, like a friction or viscous force, which almost balances the electric force. The particle would then move at very slow speed, almost following the field lines but overshooting them by a very small amount. The overshoot can be made as small as you wish by making the electric and viscous forces more nearly equal. This kind of a curve is called a tractrix.
However, we are told nothing about any other forces so we have to assume that they do not exist.