Chọn câu đúng (-7/6).(-7/6)=-49/36 -2/3.4/3=8/9

A. $\left(\frac{-7}{6}\right).\left(\frac{-7}{6}\right)=\frac{-49}{36}$

B. $-\frac{2}{3}.\frac{4}{3}=\frac{8}{9}$

C. $\frac{2}{-3}.\frac{-4}{9}=\frac{8}{27}$

D. $\frac{2}{-9}.\frac{-8}{9}=\frac{-16}{81}$