Which observation would best indicate a misfire is caused by ignition components rather than fuel delivery?

Which observation would best indicate a misfire is caused by ignition components rather than fuel delivery?

• A. A misfire that improves after swapping the coil/plug with a known good part.
• B. Misfire persists with no change after swapping ignition parts.
• C. Fuel trim data show no adaptation.
• D. Compression readings are normal across cylinders.

Answer: (A)