Latex Coder 2

What is $\displaystyle {6}\frac{2}{7} - {4}\frac{1}{7}$?
A. $ {2}\dfrac{1}{7}$
B. $ {3}\dfrac{1}{7}$
C. $ \dfrac{1}{7}$
D. ${2}\dfrac{2}{7}$
E. $ {3}\dfrac{2}{7}$