Which number is written in scientific notation?

A. 4.5 x 10^-3
B. 14.5 x 10^2
C. 0.78 x 10^-6
D. 5.7 x 4^8

Darcy deposited $390 into a savings account. as long as the account balance remains at or above $150, she does not have to pay a service fee for the account. for how many months can she withdraw $40 a month without having to pay service fees? a) 3 b) 5 c) 6 d) 9