Final answer:
The priority treatment goal for a patient with severe and persistent mental illness in a community-based setting is to independently attend to activities of daily living, which forms the basis for achieving broader social and health objectives.
Step-by-step explanation:
The priority treatment goal for a patient with severe and persistent mental illness being treated in a community-based facility is likely to be d. independently attend to activities of daily living. This goal is fundamental because it allows patients to maintain their dignity and independence, which are critical for their self-esteem and mental health recovery. Moreover, the ability to manage daily living activities is often a prerequisite for achieving other goals, such as forming new relationships, participating in community activities, and self-administering medications. Independently attending to activities of daily living ensures that individuals can take care of their most basic needs, which is essential before engaging in more complex social interactions and responsibilities.