What is the burden of proving a motion to quash?

"On a challenge to personal jurisdiction by a motion to quash, the plaintiff has the burden of proving, by a preponderance of the evidence, the factual bases justifying the exercise of jurisdiction. [Citation.] The plaintiff must come forward with affidavits and other competent evidence to carry this burden and cannot simply rely on allegations in an unverified complaint. [Citation.] If the plaintiff meets this burden, 'it becomes the defendant's burden to demonstrate that the exercise of jurisdiction would be unreasonable.'" (Buchanan v. Soto (2015) 241 Cal.App.4th 1353, 1362 (Buchanan).)