Mr Gupta asked two of his students to solve the expression \[{{\left( \frac{9{{a}^{3}}{{b}^{-8}}}{81{{a}^{-5}}{{b}^{2}}} \right)}^{-\frac{1}{2}}}\]and write the answer on blackboard. Aryan wrote the answer as \[3{{a}^{-4}}{{b}^{5}}\] whereas Ayan wrote the answer as \[\frac{3{{b}^{5}}}{{{a}^{4}}}\]. Who wrote the correct answer?

• A.  Aryan
• B.  Ayan
• C.  Both of them
• D.  None of these