Write an Equation to Describe the Variation $x = \frac { k } { s }$

Multiple Choice

Write an equation to describe the variation. Use k for the constant of proportionality.
-x varies inversely as s

A) $x = \frac { k } { s }$
B) $s = \frac { x } { k }$
C) s = kx
D) $x = \frac { s } { k }$