The correct option is A Straight line
As initially the particle is at rest,
The magnetic field won't act and Electric field gives the particle motion
in direction parallel to →E
Now when the particle gains motion,
but v ||E and E || B,
Ultimately v || B,
Hence there will be no magnetic force acting on tje particle to deviate its path,
Hence the Particles motion wil be always straight.
Option A is the correct answer.