BoTeck is a full-service technology company. It provides equipment, installation services, and training services. For a recent major group sale, the transaction price had a variable component contingent upon a threshold being reached. Revenue allocated to equipment and installation services was recognized in fiscal year 2019; revenue allocated to training services is being recognized over the next two years through the end of 2021. Now, in February 2020, the contingent outcome previously expected has proven to be false and the transaction price has changed such that additional revenue should be recognized for these performance obligations. What is the proper accounting for this change in transaction price for equipment and installation services?

A. increase 2020 and 2021 revenue by allocating adjustment equally to each year for the proportional amount of change

B. increase 2020 revenue by allocating adjustment to January and February equally to each month for the proportional amount of change

C. prior period adjustment to increase 2019 revenue for the full amount of change

D. increase 2020 revenue by adjusting February for the full amount of change