The expression $\frac{\partial \phi }{\partial t} + \int \frac{\partial \rho }{\rho } + \frac{1}{2}\left [ \Delta \phi \right ]^{2} + gz = constant$ represents
a. Steady flow energy equation
b. Unsteady irrotational Bernoulli’s equation
c. Steady rotational Bernoulli’s equation
d. Unsteady rotational Bernoulli’s equation