Express the Statement as a Formula That Involves the Variables $k = 17$

Multiple Choice

Express the statement as a formula that involves the variables w, z, u and a constant of proportionality k, and then determine the value of k from the condition : w varies directly as z and inversely as the square root of u, if z = 3 and u = 4, then w = 18

A) $k = 17$
B) $k = \frac { 1 } { 27 }$
C) $k = \frac { 1 } { 12 }$
D) $k = 12$
E) $k = 27$