A reference point, a direction and displacement together give a complete description of what?? A) force B) speed C) motion

A reference point, a direction and displacement gives an idea of motion (among the available options). Force is a product of mass and acceleration of an object, as described by Newton's Second Law of Motion (F = m x a). Here, we are not given either the mass or acceleration of the object and hence force cannot be determined from the given information. Speed of an object is the ratio of distance traveled and time taken. Here, we have the displacement (not distance traveled) and are not given the time, hence speed cannot be calculated from the given information. Given the time, we could have calculated the velocity of the object, as the ratio of displacement and time. We can only get a description of motion from the given data.

Hope this helps.