Q. A....is an imaginary line within the flow so that the tangent at any point on it indicates the velocity at that point.

• (A) ...is an imaginary line within the flow so that the tangent at any point on it indicates the velocity at that point.
• (B) In which the flow cannot cross the bounding surface
• (C) Which has a constant area throughout its length so that the velocity remains constant.
• (D) None of the above.