The answer is A. No.
Although there is no comprehensive federal drug-testing law, states regulate the use of drug testing programs, and while some establish that testing has to be performed under "reasonable suspicion" or "probable cause" situations, others explicitly authorize random testing under other circumstances.
As a general rule, testing is considered to be lawful unless there is a determined restriction in state or federal law. Since this is not specified in Simon's case, testing after his accident can help decide whether drugs or alcohol were a factor, and by doing it his employer is acting within the law. Anyways, this testing should always be performed under pre-established criteria.