Rebecca stops at a store to buy some scarves and 2 purses. The scarves cost $5 each, and each purse costs $12. Rebecca spent a total of $39 for the purchases. Write an equation to find the number of scarves bought and then solve the equation for the scarves purchased.
a) (5s + 2 × 12 = 39)
b) (5s - 2 × 12 = 39)
c) (5s + 12 = 39)
d) (5s - 12 = 39)