Simplify the Rational Expression $$c = 64 ( n + 4 ) ^ { 1 / 2 }$$

Multiple Choice

Simplify the rational expression. Use factoring, and assume all variable expressions represent positive real numbers.
-The cost of manufacturing clocks is given by c $$c = 64 ( n + 4 ) ^ { 1 / 2 }$$ , where c is the cost in dollars and n is the number produced. What is the cost when no clocks are produced?

A) $64
B) $16
C) $256
D) $128