The answer is B.
This is because A is incorrect, Zach number of minutes didnt increase by an equal factor every month.
C and D are incorrect, Victoria's methods aren't exponential, but Zach's are.
So that leaves the only reasonable answer which is B.
7 is a prime number, which means it can't be simplified. This fraction is already in simplest form, also because 25 and 7 don't have any common factors.
Answer:
C
Step-by-step explanation: