Đặt a = log 2 3; b = log 2 5; c = log 2 7.

A. ${\log }_{60}1050=\frac{1+a+b+2c}{1+2a+b}$

B. ${\log }_{60}1050=\frac{1+a+2b+c}{1+2a+b}$

C. ${\log }_{60}1050=\frac{1+2a+b+c}{2+a+b}$

D. ${\log }_{60}1050=\frac{1+a+2b+c}{2+a+b}$