; (B) the total sales volume and revenue generated by each product and service on a monthly basis for the preceding year; (C) trends in the markets filled by each product and service; (D) products and services identified in the innovation strategy that are to be discontinued, the date on which the discontinuance will occur, and the reasons for the discontinuance; (E) alterations in products and services identified in the innovation strategy that will be made to meet changing market conditions, and an explanation of how these alterations will ensure the success of the products and services; and (F) the performance of the innovation strategy according to the metrics identified in subsection (d)(2)(G). (f) Comptroller General study (1) In general The Comptroller General shall conduct a study on the implementation of the innovation strategy described under subsection (d) not later than 4 years after the date of enactment of the Postal Service Reform Act of 2018. (2) Contents The study required under paragraph (1) shall assess the effectiveness of the Postal Service in identifying, developing, and selling innovative postal and nonpostal products and services. The study shall also include— (A) an audit of the costs of developing each innovative postal and nonpostal product and service developed or offered by the Postal Service during the period beginning on the date of enactment of the Postal Service Reform Act of 2018 and ending 4 years after such date; (B) the sales volume of each such product and service; (C) the revenues and profits generated by each such product and service