Which of the following is NOT a reason a suspect cannot submit to a chemical test?

A suspect's unwillingness to comply with a chemical test does not constitute a legitimate reason for their inability to submit to such a test. The other options provide valid circumstances where a test cannot be conducted. For example, if a medical condition prevents the suspect from safely undergoing the test, that is a verifiable reason, especially if backed by a doctor's statement. Similarly, if law enforcement fails to provide the specific test that the suspect selected, or if a physician on the scene refuses to allow the test based on medical grounds, those situations are grounded in external validation and legal considerations.

In contrast, an individual’s simple refusal lacks the necessary justification. Law enforcement can proceed under existing laws to compel a chemical test under certain conditions, making the suspect's unwillingness a less significant factor compared to the others listed.