Guitar Center, the largest retail seller of musical instruments in the United States, sold guitars and amplifiers manufactured by Fender, Gibson, and three other companies. Guitar Center pressured the manufacturers to adopt and enforce minimum-advertisedprice (MAP) policies that fixed the minimum price at which any retailer could advertise the manufacturers’ guitars and amplifiers. The manufacturers then adopted similar advertising policies. Plaintiff guitar and amplifier purchasers sued Guitar Center, the manufacturer, and others claiming horizontal and vertical price fixing. The plaintiffs’ lawsuit failed. Explain how parallel behavior by the manufacturers as instructed by a retailer with market power was not a Sherman Act violation. See In Re: Musical Instruments and Equipment Antitrust Litigation, 798 F.3d 1186 (2015).