This is definitely the classic question type; "Choose the most correct answer.".
Though answer C was correct, answer B was most correct, and for the following reasons.
1. The handbook instructed that you make a resonable attempt to find the owner of the damaged property. It is not always possible to do so. However, it is always possible to leave your name, address, phone-number, and owner of the vehicle creating the damage. Therefore, answer B, which states that you should leave your name, number, and as much pertinent information as possible, is always the possible solution. The same can't be said of answer C. And that is why your son got the question wrong.
Now, that being said, it is often difficult to differentiate between 2 close answers, especially when both are correct and found in the study material. The question given on the test is used to evaluate your son's ability to choose a correct course of action, not whether or not he studied the material.
If answer C were the correct answer, then when the owner of the damaged property could not be found, the responibility for restitution would be removed from the party who damaged the property, and that couldn't satisfy the law of justice.
I know, I talk too much. But I hope I shed some light on the question.
Seeeeeya; Goodweed of the North