The correct answer is: D. involves zero transverse component of flow.
A one-dimensional flow is a flow in which the velocity vector has only one non-zero component. This means that the flow is in a straight line and there is no variation in the velocity vector in the direction perpendicular to the flow.
Option A is incorrect because a uniform flow is a flow in which the velocity vector is constant in both space and time.
Option B is incorrect because a steady uniform flow is a flow in which the velocity vector is constant in space and time, and the flow is in a straight line.
Option C is incorrect because a flow that takes place in straight lines is not necessarily a one-dimensional flow. For example, a flow in a pipe is not a one-dimensional flow, even though it takes place in straight lines.
I hope this helps!