In a streamline flow

The correct option is: The speed of a particle always remains same

Explanation:
Streamline flow (also known as steady flow) is a type of fluid flow in which the velocity of the fluid at any fixed point remains constant over time. This means that every particle of the fluid passing through a particular point follows the exact same path and has the same velocity (which includes both speed and direction) as the preceding particle that passed through that point.

Because the velocity at any given point along the streamline is constant with respect to time, the speed of any particle passing through a specific point also remains constant.