Find the Second-Order Partial Derivative $\frac{\partial^{2} z}{\partial x \partial y}$ When $z=\ln |2 x+9 y|$

Multiple Choice

Find the second-order partial derivative.
-Find $\frac{\partial^{2} z}{\partial x \partial y}$ when $z=\ln |2 x+9 y|$ .

A) $\frac{9}{(2 x+9 y) ^{2}}$
B) $\frac{-18}{(2 x+9 y) ^{2}}$
C) $\frac{18}{(2 x+9 y) ^{2}}$
D) $\frac{-9}{(2 x+9 y) ^{2}}$