Tatsouka 2009

What is the value of $6$ $\dfrac{3}{5}$ $-$ $\dfrac{4}{8}$?
A. $6\dfrac{1}{10}$
B. $\dfrac{7}{13}$
C. $\dfrac{14}{13}$
D. $1$
E. $\dfrac{21}{10}$