Each book in a store costs $12, and each pen costs $2. If you want to spend exactly $30, then write an equation that models this situation. Let b represent the number of books you buy, and p represent the number of pens you buy. Choose the best answer.

12p + 2b = 30

14bp = 30

not enough information

12b + 2p = 30

12p - 2b = 30