Brett has been studying a type of bacteria that doubles every month. Originally, there were 5 bacterial cells. He wants to know how many there will be after 42 months. Which equation should he use?
A a42 = 5(2)42 - 1
B a42 = 5(2)(42)
C a42 = 5(2)42
D a42 = 5(2)(42 - 1)