For What Value of the Constant B Is the Vector $\mathbf { F } ( x , y , z ) = 2 x \mathbf { i } + z \mathbf { j } + b z \mathbf { k }$

Multiple Choice

For what value of the constant b is the vector field $\mathbf { F } ( x , y , z ) = 2 x \mathbf { i } + z \mathbf { j } + b z \mathbf { k }$ incompressible?

A) $- 3$
B) $- 2$

C) $- 1$
D) $0$
E) $1$
F) $2$
G) $3$
H) No constant