Answer:
d = 0 [m]
Step-by-step explanation:
Displacement is understood as the length and direction that a body travels to move from an initial point to an endpoint.
This displacement is represented with a vector or straight line that indicates the distance of the displacement and its length.
This displacement in an easier way to understand. It is the distance between the start point and the endpoint of the journey. Since the second point is equal to the first point, since Mary returns to the same place, there is no difference between the displacement.
Therefore the displacement is zero.