9. ANSWER: C. The economy is so strong that even weak companies are profitable and paying their debts.
Junk bonds are often seen as more related to stocks than to other bonds, and they tend to do better when the economy is growing swiftly and stocks are rising. Junk bonds are one of the few bond categories in the green in 2018. Many of the bonds are issued by energy companies, which have been helped by strengthening oil prices.