What is the burden of proving that a plaintiff is a plaintiff in an anti-SLAPP action?

In the second step of the anti-SLAPP analysis, "the burden shifts to the plaintiff to demonstrate that each challenged claim based on protected activity is legally sufficient and factually substantiated. The court, without resolving evidentiary conflicts, must determine whether the plaintiff's showing, if accepted by the trier of fact, would be sufficient to sustain a favorable judgment. If not, the claim is stricken." (Baral v. Schnitt, supra, 1 Cal.5th at pp. 396.)