Answer:
The correct option is C. An encounter with an infected animal
Step-by-step explanation:
An opportunistic organism can be described as an organism that causes infection when it gets certain opportunities or certain conditions. If the opportunities are not there, then the opportunistic organism will not be able to cause infection. For example, a weakened immune system might be an opportunity for opportunistic microorganism to cause infection.
An encounter with an infected animal would not cause disease because there would be no opportunistic conditions available for the pathogen.