Solve Write the Answer as a Mixed Number as Needed $2 \frac{4}{5}$

Solve. Write the answer as a mixed number as needed.
-Brian was training to run a marathon. During the three-day period before the race he decided that he would train for a total of 12 hours. If he trained for $2 \frac{4}{5}$ hours on the first day and $2 \frac{3}{10}$ hours on the second day, how many hours would he need to train on the third day?

A) $7 \frac{9}{10}$ hours
B) $7 \frac{3}{10}$ hours
C) $6 \frac{9}{10}$ hours
D) 7 hours