Which of the following types of securities are most likely to have higher yields?

Evaluate each security type: Investment-grade municipal bonds are considered low-risk and typically have lower yields. U.S. Treasury bills are backed by the government and are among the safest investments, so they also have low yields. Certificates of deposit (CDs) from major banks are relatively safe and offer moderate yields.

Focus on corporate bonds rated below investment grade: These are often referred to as 'junk bonds.' They carry higher risk due to the lower creditworthiness of the issuer, but they offer higher yields to attract investors willing to take on that risk.