Which of the velocity fields will lead to the steady three-dimensional flow of an incompressible fluid?

u = 7 + 3x²y − 4xy²; v = 1 + 8yz² − 4y²z; w = 6 + 7xz³ − 5x²z

u = 3 − 2y²z + 4yz²; v = 2 + 6x³z² − 7x²z; w = 5 − 8x²y³ + 9xy

u = 4 − 5xy² + 7x³y; v = 5 + 6y²z − 7yz³; w = 2 − 3x²z + 6xz³

u = 9 + 3x³y − 5x²y³; v = 10 − 4y²z + 7y³z²; w = 7 + 5x²z³− 2xz²