An object is placed at 0 on a number line. it moves 3 units to the right, then 4 units to the left, and then 6 units to the right. the displacement of the object is

5 units

Let's begin by stating clear that movement is the change of position of a body at a certain time. So, during this movement, the body will have a trajectory and a displacement, being both different:

The trajectory is the path followed by the body (is a scalar magnitude).

The displacement is the distance in a straight line between the initial and final position (is a vector magnitude).

According to this, in the description of the object (figure attached) placed at 0 on a number line and moving some units to the left and some oter units to the right, we are talking about the path followed by the object, hence its trajectory. So, 13 units is its trajectory.

But, if we talk about displacement, we have to draw a straight line between the initial position of the object (point 0) to its final position (point 5).

Now, being this an unidimensional problem, the displacement vector for this object is 5 units.

it would be c. predictability