Calculate the yield $to$ maturity for each $of$ the following one$-$year coupon bonds. All three bonds have a face value $of$ $$100.$ Explain why the first bond has the highest yield $to$ maturity despite having the lowest coupon rate.

$(a.)A6\%$ coupon bond selling for $$85$

$(b.)A7\%$ coupon bond selling for $$100$

$(c.)An8\%$ coupon bond selling for $$115$