Answer
(a) Accelerates to the Right.
(b) Remains in place
(c) Accelerates to the Left.
Work Step by Step
(a) Since, charge is positive , hence it will accelerate along the direction of the electric field.
(b) Since, a neutral object is placed , hence, $ F=qE=0$ , so the object will remain where it is.
(c) Since, charge is negative , hence it will accelerate opposite the direction of the electric field.
Hence,
(a) Accelerates to the Right.
(b) Remains in place
(c) Accelerates to the Left.
