A plaintiff sued a defendant for libel. After the plaintiff testified that the defendant wrote to the plaintiff's employer that the plaintiff was a thief, the defendant offers evidence that the plaintiff once stole money from a former employer. The evidence of the plaintiff's prior theft is: Question 20 options: a) admissible, as substantive evidence to prove that the plaintiff is a thief. b) admissible, but only to impeach the plaintiff's credibility. c) inadmissible, because character may not be shown by specific instances of conduct. d) inadmissible, because such evidence is more unfairly prejudicial than probative