A certain Social Security recipient will r

问题：

A certain Social Security recipient will receive an annual benefit of $12,000 provided he has annual earnings of $9,360 or less, but the benefit will be reduced by $1 for every $3 of annual earnings over $9,360. What amount of total annual earnings would result in a 50 percent reduction in the recipient’s annual Social Security benefit (Assume Social Security benefits are not counted as part of annual earnings.)（）

A.$15，360

B.$17，360

C.$18，000

D.$21，360

E.$27，360