In the state of California, the CPI in 2020 was 251.1 and the CPI in 2022 was 294.4. Jake, a resident of California, borrowed money in 2020 and repaid the loan in 2022. If the nominal interest rate on the loan was 12 percent, what was the real interest rate?
a. -5.24 percent
b. 12.00 percent
c. 9.28 percent
d. 2.00 percent