Answer:
The correct option is (a).
Explanation:
We have, a negative test charge experiences a force to the right as a result of an electric field. The electric force acting on a charged particle is given by :
F = qE
q is charged particle, E is electric field
The direction of electric force is in the direction of electric field. For a negative charge, the electric field points to the left because the force on a negative charge is opposite to the direction of the field.