Find K Such That $3 ^{- x / 2}$ = $\mathrm { e } ^ { \mathrm { kx } }$

Multiple Choice

Find k such that $3 ^{- x / 2}$ = $\mathrm { e } ^ { \mathrm { kx } }$ for all x.

A) - $\frac { 1 } { 2 }$ ln 3
B) ln 3
C) $\frac { 1 } { 2 }$ ln 3
D) ln - $\frac { 3 } { 2 }$