Tatsouka 2009

What is the value of $6$ $\dfrac{2}{4}$ $-$ $4$ $\dfrac{5}{6}$?
A. $1\dfrac{2}{3}$
B. $\dfrac{7}{10}$
C. $\dfrac{11}{10}$
D. $1$
E. $\dfrac{7}{3}$