4. (Long Term Liabilities Bonds and Notes) (CPMKP, 2) (Weight: 20%) On January 1, 2019, PT Borobudur issued a 5-year bond with a 6% coupon. Interest payments are made once a year, starting January 1, 2020. The face amount of the bonds is IDR 100,000,000. a. On January 1, 2019, PT Muara Takus issued a bond with a tenor of 6 years. The bond with a face value of IDR 50,000,000 promises a 5% coupon, which is paid twice a year, on June 30 and December 31. b. On July 31, 2019, PT Kalasan issued a three-year bond with a principal of IDR 60,000,000. There is a 10% coupon that is paid four times a year, on October 31, January 31, April 30, and July 31. c. On January 1, 2019, PT Plaosan issued a four-year bond with a coupon of 8%, which is paid twice a year, namely on July 31 and January 1. The principal value of the bonds issued by PT Plaosan is IDR 100,000,000. It is known that the market interest rate throughout 2019 was 8%. Determine whether the above bonds sold at a premium, par, or discount, and state why