So we can ignore the endings because they all have to same endings. We know that 10^2 = 100 We see only 2 answers that have that a and b. But we also need to get the n to the power. So we power each number in the parenthesis by 2. Only A lets you power both 10 and n at the same time.
Because if you start with one dollar and by day 3 you get 301 dollars and option A only gives you 8 cents on day 3 you get more money by the end of the month if you choose option B.
