3. why would someone who rides in an ambulance carrying a patient with an airborne communicable disease be considered to have been exposed?

If the disease is communicable, it is contagious. If it is airborne, it is transferred through the air, as opposed to physical touch or blood-borne. Being in a confined space, such as an ambulance, with an airborne communicable disease means you have most definitely been exposed to it.

The answer is 3) taking ownership of the decision