Write the Word or Phrase That Best Completes Each Statement $\sqrt { - 324 }$

Multiple Choice

Write the word or phrase that best completes each statement or answers the question.
Provide an appropriate response.
- $\sqrt { - 324 }$

A) $\pm 18$
B) $- \mathrm { i } \sqrt { 18 }$
C) $- 18 \mathrm { i }$
D) $18 \mathrm { i }$