Write the Equation That Expresses the Relationship Between the Variables $z$

Multiple Choice

Write the equation that expresses the relationship between the variables described below, then use the given data to solve for the variation of constant. "y varies directly as $z$ , and $y = 86.66$ when $z = 14.$ "

A) $y = \frac { k } { z }$ ; $k = 1213.24$
B) $y = \sqrt { k } z$ ; $k = 38.32$
C) $y = k z$ ; $k = 6.19$
D) $y = k ^ { 2 } z$ ; $k = 2.49$
E) $y = \sqrt { k z }$ ; $k = 536.43$