A Miscalculation #4

This calculator was purchased from PDQ Drug Store.  Sludge reprogrammed it so it gives incorrect answers:
1 + 2 = 5
2 + 3 = 8
1 + 3 = 7
2 + 2 = 6

What will this calculator show when you enter 3 + 3 =
a. 8
b. 9
c. 10