The answer is A: could have Jack struck from the panel for cause.
Explanation for each option:
A. Could have Jack struck from the panel for cause: This is the correct answer. In legal proceedings, a potential juror can be struck from the jury panel for cause if there is a legitimate reason to believe that the juror cannot be impartial. Since Jack Knighton works for PRG Consulting, which has Renar Corporation as a client, there is a potential conflict of interest. The attorney for the plaintiff could argue that Jack might be biased in favor of Renar Corporation due to his professional connection, and thus, could have him struck from the panel for cause.
B. Cannot have Jack struck just because his company has the defendant as a client: This statement is incorrect. The professional relationship between Jack's employer and the defendant could be seen as a potential source of bias, which is a valid reason to strike a juror for cause.
C. None of these answers: This is incorrect because option A provides a valid reason for striking Jack from the jury panel.
D. Has no recourse because the jury is a wild card in litigation: This is incorrect. Attorneys have the right to challenge potential jurors for cause if there is a reason to believe they cannot be impartial. The jury is not entirely a "wild card" as there are mechanisms in place to ensure a fair and impartial jury.
In summary, the attorney for the plaintiff could have Jack struck from the panel for cause due to the potential conflict of interest arising from his company's relationship with the defendant.