a. True. Corporate bonds have higher yields than T-bonds because they have higher credit and liquidity risks. T-bonds are issued by the U.S. government and are considered to have a low risk of default, while corporate bonds are issued by companies and have a higher risk of default. Additionally, the market for T-bonds is generally more liquid than the market for corporate bonds. As a result, investors demand a higher yield to compensate for the added risks associated with corporate bonds.