Chang, a brain surgeon, subscribes to the Journal of Brain Research. With a special subscription offer, Chang

Question:

Chang, a brain surgeon, subscribes to the Journal of Brain Research. With a special subscription offer, Chang pays $ 3,000 this year for the full three-year subscription for this weekly scientific journal. Normally, the journal charges $ 1,500 for an annual renewal. In what year(s) can Chang deduct this $ 3,000?