Find the Critical Points Of $f ( x ) = \frac { \ln 4 x } { 2 x }$

Multiple Choice

Find the critical points of $f ( x ) = \frac { \ln 4 x } { 2 x }$

A) 0
B) $\frac { 1 } { 2 } e$
C) $\frac { 1 } { 4 } e$
D) 1