Final answer:
Barb would be categorized as functionally competent. Despite using a walker, she is able to live independently in an apartment.
Step-by-step explanation:
Based on the information provided, Barb would be categorized as functionally competent. While she uses a walker regularly, she still lives independently in an apartment, which suggests she has the ability to perform activities of daily living and manage her own affairs. Being functionally competent means that, despite any physical limitations or need for assistive devices, an individual is able to navigate their environment and maintain a certain level of independence.