You bought 500 forever stamps just before the price went up in January of 2014 at $0.46/stamp, a $0.03 savings per stamp. If you could have paid off a credit card charging 12% per year instead of investing in stamps, how fast must you use the stamps to breakeven? Assume the $0.49 price never changes before you run out of stamps. (Hint use 12% / year as your effective interest rate per year)

a. 3 months

b 6 months

c 10 months

d 12 months

e 36 months