Who may legally require you to give a blood sample?

Answer: B — police officer

The legal requirement to provide a blood sample can arise in situations involving law enforcement, particularly when a police officer suspects that an individual is under the influence of drugs or alcohol while operating a vehicle. This authority is granted under certain laws related to road safety and impairment assessments. When a police officer has reasonable grounds, they can compel an individual to undergo a blood test to determine blood alcohol concentration or the presence of illegal substances. This process is critical in maintaining public safety on the roads, as it helps identify and penalize impaired driving. In contrast, while a doctor can request blood samples for medical reasons, they do not have the legal authority to enforce a blood sample on the basis of road traffic offenses. Traffic wardens typically focus on parking regulations, and their role does not extend to demanding blood samples. Paramedics provide emergency care and may take blood samples for medical analysis, but again, they do not have the legal power to require a sample in the context of suspected driving offenses.