How do you compute a compass correction (deviation) for a vessel?

How do you compute a compass correction (deviation) for a vessel?

• A. Determine the deviation by comparing the ship’s compass reading to a known fix or radar position; apply the difference to obtain true/magnetic headings.
• B. Use the ship's speed to estimate deviation.
• C. Deviation is fixed and does not need calculation.
• D. Compare celestial observations to determine deviation.

Answer: (A)