Kindly solve using legit formulas and not excel's pre-packaged formulas. Thank you

YMMV Inc. issues a bond with a face value of $70,000,000 with a coupon rate of 1.750% maturing in 15 years. The current yield rate is r(26) = 4.250%. TFC will secure the bond by making annual deposits into a sinking fund paying 4.750% compounded weekly. YMMV defaults on the bond after 11 years (just after making their coupon payment, and sinking fund deposit). The bondholders receive the balance in the sinking fund. How much money do they lose? a. $16,599,562.06. b. $17,291,210.47. C. $20,057,804.15. d. $17,118,298.37. e. $16,945,386.27