Determine the Constant of Variation for the Stated Condition $c$ Varies Directly As

Multiple Choice

Determine the constant of variation for the stated condition.
- $c$ varies directly as $a$ and inversely as $b ; c = 5$ when $a = 65$ and $b = 117$

A) $\mathrm { c } = \frac { 9 \mathrm { a } } { \mathrm { b } }$
B) $c = \frac { a } { 9 b }$
C) $c = 9 a b$
D) $c = \frac { 9 } { a b }$