A private investigator is asked by opposing counsel during cross-examination to speculate on the motives of the subject of their investigation. How should the PI respond?

1. Politely ask the judge for guidance on whether to answer.
2. Offer an informed opinion based on their extensive experience.
3. Refuse to answer the question entirely, citing confidentiality.
4. State that providing speculation is not within their role or professional capacity as a factual witness.