The prime rate is the base rate for any financial transaction. The prime rate is considered for each type of lending instruments by the bank. bank add a margin % over the prime rate and offer loan/instrument at the increased rate.
In the given case, the BestBank's Visa credit card discloses an A.P.R. of "Prime Rate + 5.74% to Prime Rate + 22.74%, which means the A.P.R is calculated on the basis of Prime rate and any change in prime rate will directly affect the A.P.R.
The Prime Rate has increased from 3.25% to 4.25%, it means the increase of 1%. Hence the A.P.R. Shall also increase by 1%.
Hence the correct answer is:
b. Increase in A.P.R by 1%