Final Answer:
Emma most likely contracted the bacteria causing Rocky Mountain spotted fever through Tick bite. The disease is primarily transmitted to humans through the bite of infected ticks, not through ingestion, airborne transmission, or direct contact with an infected person. The answer is OPTION 3: Tick bite.
Step-by-step explanation:
Emma most likely contracted the bacteria causing Rocky Mountain spotted fever through OPTION 3: Tick bite. This infectious disease is primarily transmitted to humans through the bite of an infected tick, particularly the American dog tick (Dermacentor variabilis) or the Rocky Mountain wood tick (Dermacentor andersoni). These ticks serve as vectors for the bacterium Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever.
The bacteria are transmitted through the saliva of the infected tick during a blood meal. Ingestion (Option 1), airborne transmission (Option 2), and direct contact with an infected person (Option 4) are not typical modes of transmission for Rocky Mountain spotted fever.