If the yield to maturity (the market rate of return) of a bond is less than its coupon rate, the bond should be? and why?

selling at a discount, i.e. the bond's market price should be less than its face (maturity) value

selling at a premium, i.e, the bond's market price should be greater than its face value.

selling at par; i.e, the bond's market price should be the same as its face value.

purchased because it is a good deal