Jack performs services for Jill in November 2016. Jack sends Jill an invoice for $13,000 on December 1, 2016.

Jack preforms services for Jill in November 2016. Jack sends Jill an invoice for $13,000 on December 1, 2016. The invoice is due December 15, 2016. On December 14, 2016, Jill stops by Jack's office and tries to pay Jack. Jack declines to accept the money and tells Jill to come back after the first of the year to pay. Jill agrees. Jill returns on January 4, 2017 and pays Jack $13,000. In what year must Jack recognize the $13,000 income