Naomi pays $1.50 each time she rides the city bus. She has already ridden the bus 18 times so far this year. The expression 1.50b+1.50(18) represents the amount of money she expects to spend on bus rides for the entire year.
What part of the expression represents the amount of money Naomi expects to spend on bus rides between now and the end of the year?
A
b
B
1.50
C
1.50b
D
1.50(18)