Elppa Inc. is a calendar year, accrual method C corporation. In December 2016, Elppa enters into a parking lot renovation contract with XYZ pursuant to which Elppa pays XYZ $200,000. Elppa expects that the renovation will be completed by the end of February 2017. In January 2017, XYZ comments renovating the parking lot, and in February 2017, the renovation is completed. When does economic performance occur? When can Elppa deduct the $200,000 payment?