Final answer:
The client who needs assistance with ambulation and is cared for by her adult child is at an additional risk for maltreatment.
Step-by-step explanation:
In assessing an older adult client for additional risk factors for maltreatment, a community health nurse should recognize that the client who needs assistance with ambulation and is cared for by her adult child (option B) has an additional risk factor for maltreatment. This is because the client is dependent on her adult child for care, which can increase the potential for abuse or neglect. In contrast, the other options involve clients who receive care in facilities or from healthcare professionals, reducing the risk of maltreatment.