Let's look at a possible exam question on everybody's favorite topic: bond yields.
S&P just downgraded a corporate bond, pushing the bond’s yield
D. in a bond-ladder direction
EXPLANATION: if the rating goes down, so does the “quality,” which means the price falls. And, when the price falls, the yield rises. Would you pay as much for a junk bond as you'd pay for a Treasury bond? Not a chance--the riskier bonds cost less and yield more.