Use Properties of Logarithms to Evaluate the Expression $\mathrm { f } ( \mathrm { x } ) = \log 7 x$

Multiple Choice

Use properties of logarithms to evaluate the expression.
-If $\mathrm { f } ( \mathrm { x } ) = \log 7 x$ , find $f \left( 7 ^ { 8 } \right)$

A) 8
B) $\log 8 x$
C) 7
D) 56