What are the $3$ classifications of protected$/$privileged evidence that may not be discoverable in data breach or cybersecurity litigation.$$

attorney$-$client privilege, work product doctrine, and non$-$testifying expert

attorney$-$client privilege, work product doctrine, and all IT software engineers employed by the defendant

attorney$-$client privilege, work product doctrine, and all IT design engineers employed by the defendant

attorney$-$client privilege, IT repair product doctrine, and all IT employees of the defendant