A basic rule of finance is that

The bond price and interest rate moves in opposite direction. As the rate of interest rises, the bond price falls and viceversa. When the rate of interest goes up the existing bond will be sold at a discount on par value. When the rate of interest falls the existing bonds will be sold at a premium on par value. Suppose the bonds are issued at a rate of 10% interest on maturity. When the rate of interest goes up to 15% the issued bonds will be sold at a lower rate of its face value because while investing in new bonds the people can get 15%. On the other hand when the rate of interest falls to 8% the new bonds will be issue at a rate of 8%. This time by buying the existing bonds the people can earn 10%. Thus the existing bonds will be traded at premium.

c. Bond prices and interest rates move in the opposite direction.