Find the Modulus and the Argument for the Complex Number $z = - i$

Multiple Choice

Find the modulus and the argument for the complex number. $z = - i$

A) $r = - 1 , \theta = \frac { \pi } { 2 }$
B) $r = 1 , \theta = \pi$
C) $r = i , \theta = 0$
D) $r = \sqrt { 2 } , \theta = \frac { 3 \pi } { 2 }$
E) $r = 1 , \theta = \frac { 3 \pi } { 2 }$