The knowledge point examined in this question is the time limit for invalidation of patent right. 1. According to the provisions of Article 46 of the Patent Law, anyone who refuses to accept the decision of the Patent Reexamination Board to declare the patent right invalid or maintain the patent right may bring a lawsuit to the people's court within three months from the date of receiving the notice. The people's court shall notify the other party to the procedure for requesting invalidation to participate in the proceedings as a third party. Therefore, the correct answer is C.