Step 1: Understand the term "abettor''
- An abettor is someone who encourages, aids, or helps another person to commit a crime.
- They may not commit the crime themselves but support or assist the main offender.
Step 2: Other options
- (B) Power of attorney is a legal document, unrelated.
- (C) Legal defense is a strategy, not an abettor.
- (D) Formal accusation is a charge, not a person.
Thus, option (A) is correct.