I'd go with option C as well.
Reminds me of a flight on the backseat of an EC120 in Asia a few moons ago.
Me to driver: "Uhh, did you notice your chip light just came on?".
Driver: "Don't worry, happens all the time."
Driver: "It will go away in a few minutes."
Driver: "It's just a small metal..."
(continues to tell me how a chip light works)
Turns out they were flying that lovely EC120 with chip light all the time and couldn't find what the culprit was (my suspicion: the maintenance center was very far away).