Final answer:
The best device to remove extrinsic stains on the facial surfaces of teeth #23 through #25 is prophylaxis paste.
Step-by-step explanation:
The best device to remove extrinsic stains on the facial surfaces of teeth #23 through #25 would be a prophylaxis paste (option a).
Prophylaxis paste is a polishing agent used during dental cleanings to remove stains and plaque buildup on the teeth. It contains abrasive particles that help to scrub away the stains.
The other options, such as ultrasonic scalers (option b), hand scalers (option c), and dental floss (option d), are not as effective in removing surface stains.