Answer:
a) The bond sells at a price below par.
Explanation:
It means that the investor needs to pay a price lower than the par value the get a treasury bond, the coupons are fixed and the return of the principal it's the same as issued, if the yield to maturity (7,5%, discount rate in the present value formula) it's less than the rate of coupons (8%), then the price must be lower than the par value to meet the result.
When the bonds are traded at par value it means that the coupon rate it's the same of the yield to maturity.
And fi the bonds are traded at a price above par then the price of the bond are higher than the issued price.