Find the Equation of Variation If the Following Is True $y$

Multiple Choice

Find the equation of variation if the following is true.
-Suppose $y$ varies directly as $x$ and $y = 0.9$ when $x = 0.1$ .

A) $y = 9 x$
B) $\mathrm { y } = 1 \mathrm { x }$
C) $y = \frac { 1 } { 9 } x$
D) $\mathrm { y } = 0.8 \mathrm { x }$