Answer
Point A - Down and to the left parallel to the field lines.
Point B - Up and to the right, parallel to the field lines.
Point C - Net force is zero.
Work Step by Step
At point A, the direction of the net force on a positive test charge is down and to the left, parallel to nearby electric field lines.
At point B, the direction of the net force on a positive test charge is up and to the right, again, parallel to nearby electric field lines.
At point C, by symmetry the net force on a positive test charge is 0.
You can check the spacing of the field lines to determine strength. In order of decreasing field strength, the points are A, B, C.
