Solve the Equation and Express the Solution in Exact Form $\ln 9 x + \ln 7 x = \ln 64$

Multiple Choice

Solve the equation and express the solution in exact form.
- $\ln 9 x + \ln 7 x = \ln 64$

A) $\left\{ \frac { e ^ { 64 } } { 63 } \right\}$
B) $\{ 1 \}$
C) $\{ 0 \}$
D) $\left\{ \left( \frac { 64 } { 63 } \right) ^ { 1 / 2 } \right\}$