Can an object reverse its direction of travel while maintaining a constant acceleration?
1. yes; a ball thrown toward a wall bounces back from the wall.
2. all are wrong.
3. no; the direction of the speed is always

If an object has a constant acceleration, then his velocity is creasing in the same direction has te acceleration, ence you are moving in the same direction as the acceleration (unless the acceleration is 0, and you have constant speed). So if the acceleration is constant, an object cannot reverse the direction of travel, because this would mean that also the velocity changes the direction.

The answer here is 2: all are wrong.