Answer:D. mutualist, pathogen, nutrient recycler
Explanation:in mutualism,both the leave and the plants benefits from each other
Then as the bacteria moves into the plant,it becomes a pathogen to the plant , living off the plant and causing diseases
As the plant dies,the bacteria helps to break down and decompose the plant and return the initial nutrients in the plant back to the environment.this activity of the bacteria ensures that nutrients are continually Available to be reused