The answer is C. "12 miles."
If you travel 10 miles north, that translates into a positive 10. Travelling 6 miles south, in this case, can be equated into negative 6.
So we have:
10-6=4
If you travel 8 miles north to the bank, then that's another positive 8.
So then it becomes:
4+8=12
The total distance travelled is 12 miles.