Consider the following statements for a two- dimensional potential flow: 1. Laplace equation for stream function must be satisfied. 2. Laplace equation for velocity potential must be satisfied. 3. Stremlines and equipotential lines are mutually perpendicular. 4. Streamlines can intersect each other in very high speed flows. Which of the above statement s are correct?

• A. 1 and 4            
• B. 2 and 4       
• C. 1, 2 and 3                     
• D. 2, 3 and 4