Tính giá trị \(A = \frac{{7!4!}}{{10!}}\left( {\frac{{8!}}{{3!5!}} - \frac{{9!}}{{2!7!}}} \right)\) A. \(A = \frac{4}{5}\) B. \(A = \frac{5}{4}\) C. \(A = \frac{2}{3}\) D. \(A = \frac{6}{7}\)
