Which of the Following Effectively Ended the Reserve Clause

Which of the following effectively ended the reserve clause?

A) The formation of the Brotherhood of Professional Baseball Players, led by John Montgomery Ward, which led to the formation of the Players League.
B) The Federal League's lawsuit claiming the reserve system was an anti-trust violation that kept them from acquiring the talent necessary to compete equally.
C) A lawsuit initiated by Curt Flood, who challenged the right of the St. Louis Cardinals to trade him to the Philadelphia Phillies.
D) A salary arbitration hearing where arbitrator Peter Seitz decreed that Andy Messersmith was no longer contractually bound to the Los Angeles Dodgers.