Use the Rules of Exponents to Simplify the Expression $z^{-2 / 7} \cdot z^{3 / 7}$

Multiple Choice

Use the rules of exponents to simplify the expression. Write the answer with positive exponents. Assume that all variables represent positive real numbers.
- $z^{-2 / 7} \cdot z^{3 / 7}$

A) $z^{1 / 7}$

B) $z^{6 / 7}$

C) $z^{-1 / 7}$

D) $z^{7 / 6}$