Simplify the Expression $\left( \frac { c } { a } \right) ^ { 0 }$

Multiple Choice

Simplify the expression. Remove all negative and zero exponents. Assume the expression is defined. $\left( \frac { c } { a } \right) ^ { 0 }$

A) $\left( \frac { \mathrm { c } } { \mathrm { a } } \right)$
B) $\left( \frac { c } { a } \right) ^ { - 1 }$
C) $\left( \frac { c } { a } \right) ^ { 2 }$
D) 0
E) 1