An entity receive a seven-year zero interest-bearing note on february 1, 2017 in exchange for property sold. there was no established exchange price for the property and the note has no ready market. The prevailing rate of interest for a note of this type was 7% on February 1, 2017, 6% on December 31, 2017, 8% on February 1, 2018, and 9% on December 31, 2018. What Interest rate should be used to calculate the interest revenue from this transaction for the years ended December 31, 2017 and 2018, respectively?

a. 0% and 0% b. 7% and 7% c. 7% and 9% d. 6% and 9%