Gabriella is going back to school shopping. Each notebook she buys cost $3 and each pack of markers costs $3. She buys 4 packs of markers and "n" notebooks. She writes the following expression to represent how much she spends: 12+3n Which of the following is another expression she could have written to represent how much she spends?
3 x 4n
3(4+n)
9 x 3n
6(4+n)