One of the reasons the court ruled against napster was: a. it knowingly encouraged and assisted in the infringement of copyrights b. it knowingly stored illegal copies of files on its server c. it knowingly used technology protected by patent d. all of the above

a. it knowingly encouraged and assisted in the infringement of copyrights

The specific language of the appeals court ruling against Napster in 2001 stated that Napster "knowingly encourages and assists its users to infringe the record companies' copyrights." The official case was A&M Records, Inc. v. Napster, Inc., and the US Court of Appeals for the Ninth Circuit affirmed the ruling that had been made by the US District Court for the Northern District of California.