Does Tillman need to discredit all of the District's legitimate reasons for not smoking on school grounds?

Tillman argues that he presented evidence that the complaint that he had smoked on school grounds was not credible, generating an inference of pretext. He argues that he is not required to discredit each of the District's legitimate reasons, and he satisfied his burden to demonstrate a triable issue by disputing the smoking complaint. (See Tomasso v. Boeing Co. (2006) 445 F.3d 702, 707 [" 'If the defendant proffers a bagful of legitimate reasons, and the plaintiff manages to cast substantial doubt on a fair number of them, the plaintiff may not need to discredit the remainder.' "].)