\({\log _{\frac{1}{a}}}\sqrt[3]{{{a^7}}},\,\,\left...

Câu hỏi: \({\log _{\frac{1}{a}}}\sqrt[3]{{{a^7}}},\,\,\left( {a > 0,\,\,a \ne 1} \right)\) bằng:

A \( - \frac{3}{7}\).                                

B  \(\frac{7}{3}\).                                               

C \(\frac{3}{7}\).                                    

D  \( - \frac{7}{3}\).