After Determining Whether the Variation Model Below Is of the Form

Multiple Choice

After determining whether the variation model below is of the form $y = k x$ or $y = \frac { k } { x }$ ,find the value of k.
$$\begin{array} { | c | c | c | c | c | c | } \hline x & 20 & 40 & 60 & 80 & 100 \\\hline y & \frac { 1 } { 30 } & \frac { 1 } { 60 } & \frac { 1 } { 90 } & \frac { 1 } { 120 } & \frac { 1 } { 150 } \\\hline\end{array}$$

A) $k = \frac { 1 } { 20 }$
B) $k = \frac { 3 } { 2 }$
C) $k = \frac { 5 } { 4 }$
D) $k = \frac { 1 } { 10 }$
E) $k = \frac { 2 } { 3 }$