; and (D) the acceptability of the commercial marketplace, including refiners, automotive fuel retailers, manufacturers, and ultimate users, of increasing the octane sensitivity of automotive fuel with a research octane number of 95 or higher. (3) Information The Administrator shall provide the Academy, at its request, any information which the Academy determines necessary to conduct the study under paragraph (1). (b) Reports (1) Interim reports Not later than July 1, 2019, and every 6 months thereafter until a final report is submitted under paragraph (2), the Academy shall submit to Congress and the Administrator a report on the progress of the study conducted under subsection (a). (2) Final report Not later than December 31, 2021, the Academy shall submit to Congress and the Administrator a final report on the study conducted under subsection (a). (c) Definitions In this section: (1) Academy The term Academy means the National Academy of Sciences, or if the National Academy of Sciences declines to enter into an arrangement pursuant to subsection (a), another appropriate entity. (2) Administrator The term Administrator means the Administrator of the Environmental Protection Agency. (3) Octane sensitivity The term octane sensitivity means, with respect to automotive fuel used in an automotive spark-ignition engine, the difference between the research octane number and the motor octane number for such automotive fuel. (4) Research octane number and motor octane number The terms research octane number and motor octane number have the meaning given such terms in section 201 of the Petroleum Marketing Practices Act ( 15 U.S.C. 2821 ). 105. Advertisement of price of 95 RON automotive fuel (a) In general It shall be unlawful for any person to sell or offer for sale, at retail, automotive fuel with a research octane number of 95 unless such person displays, in a manner specified in the rules promulgated under subsection (b), the total price per gallon of such fuel on any sign on which such person displays the price of