$1)$ Suppose you purchased a $20-$year bond four years ago at par. The bond pays annual interest, has a par value of $$1,000$ and a coupon rate of $10\%.$ Today, the bond has $16$ years to maturity, the market rate of interest is $8\%$ and you are considering selling the bond.

a$.$ What was the market rate of interest at the time you purchased the bond? $(1$ Mark$)$

b$.$ Suppose you wish to sell the bond today; how much should you sell the bond for? $(6$ marks$)$

c$.$ What is the current yield of the bond today? $(2$ marks$)$