Solution:- Answer is 19.33%
Annual percentage rate (APR) is the yearly rate for a price which have to pay for borrowing money through credit card.
Here Caleb has an offer from a credit card issue for i=0% APR for the first 30 days.
now, effective interest rate for n= 30 days
=
After 30 days APR =17.68%=0.1768
n=365-30=335 days
now the effective interest rate for n=335 days
=
=19.33%
So the effective interest rate for 365 days =0+19.33% =19.33%
So fourth option is correct.