On 12 March 2021 Annabel bought a 180-day $100 000 bank bill for $97 500. She sold this bank bill on 24 May 2021 at 2.55% p.a. (simple interest). a) What was the (simple interest) purchase yield Annabel paid (expressed as a percentage and rounded to three decimal places)? O a. 12.821% p.a. O b. 5.199% p.a. O c. 5.348% p.a. O d. 11.276% p.a