Final answer:
Personal defenses are usable against a holder of a negotiable instrument, not against a 'holder in due course'. A holder in due course is protected from personal defenses and may enforce the instrument free from these claims.
Step-by-step explanation:
Personal defenses are claims that a person can use to avoid payment on a negotiable instrument to certain parties under specific circumstances in commercial law. When referring to personal defenses, they can be used against a holder of the instrument, but they generally do not work against a holder in due course. Therefore, the correct answer to the question 'Personal defenses are defenses that can be used against:' is c. a holder, but not a holder in due course of a negotiable instrument.
A holder in due course is a party that has acquired the instrument in good faith and without knowledge of any defects or claims; thus, they are protected from most claims that could be raised by the original parties. Personal defenses can include claims such as fraud in the inducement, non-delivery of goods, or lack of consideration; however, these defenses will be ineffective against a holder in due course, who is entitled to enforce the instrument as if such claims did not exist.