Concept:A body can accelerate even while its speed stays constant if its direction of motion changes continuously.
Explanation:Acceleration is the rate of change of velocity.
Velocity is a vector quantity, so it changes when the speed changes or when the direction changes.
The question states that the speed is constant.
Therefore, the acceleration present here must result only from a change in direction.
This situation is exactly what happens in circular motion.
For example, in uniform circular motion, the body moves with constant speed but its direction changes at every instant.
This produces centripetal acceleration, always directed toward the centre of the circle.
Oscillation is a to-and-fro movement, rotational motion is spinning about an axis, and rectilinear motion is along a straight line.
Neither oscillation nor rectilinear motion fits the condition of constant speed with acceleration.
Thus, the correct description is circular motion.
Answer:B. circular