How should Mary account for the collection?

Mary incurred a $20,000 nonbusiness bad debt last year. She also had an $18,000 long-term capital gain last year. Her taxable income for last year was $25,000. During the current year, she unexpectedly collected $12,000 on the debt. How should Mary account for the collection?

A) $0 income
B) $8,000 income
C) $11,000 income
D) $12,000 income
E) None of the above