John purchased a 90-day $500,000 bank bill (at a simple interest rate) on 15 July 2021. The purchase price was $490,550. He sold this bank bill on 13 August 2021.

(b) Assume that John sold this bank bill at a simple interest rate of 2.67% p.a. up to the maturity date of the above bank bill. What is the annualised (simple interest) yield for this investment from 15 July 2021 to 13 August 2021? Round your answer to 3 decimal places in terms of percentage.

a. 19.113% b. 18.019% c. 17.711% d. 18.547%