Which of these conditions is not met at a point for irrotational flow?

• A. \(\frac {∂w}{∂y} = \frac {∂v}{∂z}\)
• B. \(\frac {∂w}{∂x} = \frac {∂u}{∂z}\)
• C. \(\frac {∂v}{∂x} = \frac {∂u}{∂z}\)
• D. \(\frac {∂v}{∂x} = \frac {∂u}{∂y}\)