The Relationship Between Risk and Return Junk Bonds Speculative Stock Common Stock Required Return in Preferred Stock % per Year Investment-Grade Bonds Prime Commercial Paper U.S. Treasury Bills Increasing Degrees of Risk 45. From this graph, what can you conclude about U.S. Treasury Bills? a. U.S Treasury Bills are risky investments with high rates of returns. b. US. Treasury Bills are the safest investment, but are likely to yield the lowest return. c. Junk bonds have higher ratings than U.S. Treasury Bills. d. Stocks are riskier investments than junk bonds