What character is which ?

Astudent wants to replace the underlined word to make the meaning more precise.which phrase would be the best replacement for the underlined phrase ?

Cameron, who has an extreme and unreasonable suspicion of other people and their motives, suffers from paranoia which is a psychological disorder characterized by delusions of persecution or grandeur, was absolutely sure that someone was following him even though he was absolutely alone and hadn't seen a car for miles and miles.

In an essay, a strong argument does not state a clear claim. has little or no logic. uses few or no sources. is supported with sources.