Evaluate or Simplify the Following the Expression $16^{1 / 2} \div 16 ^ { - 1 / 2 }$

Evaluate or simplify the following the expression.
- $16^{1 / 2} \div 16 ^ { - 1 / 2 }$

A) $- 1$
B) 4
C) 8
D) 16