What is the magnitude of the total displacement of the school bus from the start to the end of its trip?

With the given information, we can assume that the start and the end of the trip are the same place. (Suppose, a tour where the bus starts at the school, then it goes to a given location, and then it returns to the school)

Now, the definition of displacement is:

The difference between the final position and the initial position.

But if the start and the end of the trip are the same place, then the initial and final position must be the same. Then the difference between the final position and the initial position is zero.

This means that the displacement of the school bus from the start to the end of its trip must be zero.