Today is 1 July 2020. Joan has a portfolio which consists of two different types of financial instruments (henceforth referred to as instrument A and instrument B). Joan purchased all instruments on 1 July 2015 to create this portfolio and this portfolio is composed of 30 units of instrument A and 25 units of instrument B. Instrument A is a zero-coupon bond with a face value of 100. This bond matures at par. The maturity date is 1 January 2030. Instrument B is a Treasury bond with a coupon rate of j2 = 2.78% p.a. and face value of 100. This bond matures at par. The maturity date is 1 January 2023. (a) Calculate the current price of instrument A per $100 face value. Round your answer to four decimal places. Assume the yield rate is j2 =4.72% p.a. Select one: O a. 64.1985 O b. 41.6329 O c. 50.8419 O d. 49.6697