In the U.S., copyright infringement is sometimes confronted via lawsuits in civil court, against alleged infringers directly, or against providers of services and software that support unauthorized copying. For example, major motion-picture corporation MGM Studios filed suit against P2P file-sharing services Grokster and Streamcast for their contributory role in copyright infringement. In 2005, the Supreme Court ruled in favor of MGM, holding that such services could be held liable for copyright infringement since they functioned and, indeed, willfully marketed themselves as venues for acquiring copyrighted movies. The MGM v. Grokster case did not overturn the earlier Sony decision, but rather clouded the legal waters; future designers of software capable of being used for copyright infringement were warned.

Answer this question, if possible (if impossible, reply "unanswerable"): What studio's case decision was overturned?
unanswerable