Harley signs a check payable to Pro Accountants, P.C., and gives it to Pro, leaving the amount blank but authorizing the firm to fill in the check for $10,000. Pro fills in $15,000 and then tries to collect $15,000 from Harley. Does Harley have a valid defense? Question 42 options: Yes, forgery of a signature. No, Harley should have examined the finalized check. Yes, material alteration to the instrument. Yes, a mental capacity defense