Keith McPherson Earned $20,000 Last Year as a Carpenter

Keith McPherson earned $20,000 last year as a carpenter. He paid $6,000 for food, rent, medical expenses and other "necessities." There was little construction work in February, so he took a trip to the Caribbean and spent $4,000. What was Keith's disposable income last year?

A) $4,000
B) $20,000
C) $10,000
D) $12,000
E) There is not enough information to tell.