Refer to the Illustration $C$ If $a = 4$ And $b = 3$

Multiple Choice

Refer to the illustration. Find $C$  if $a = 4$  and $b = 3$ .

A) 5
B) $\sqrt { 60 }$
C) $\sqrt { 18 }$
D) $\sqrt { 17 }$
E) 7