Final answer:
When planning care for Mr. Mathis, the nursing diagnosis that should take priority is Risk for infection.
Step-by-step explanation:
When planning care for Mr. Mathis, the nursing diagnosis that should take priority depends on his specific condition and needs. However, if we consider the options given, the nursing diagnosis that might take priority would be Risk for infection. This is because infections can have severe consequences and can potentially lead to other health complications. It is essential to prevent and manage infections to promote overall health and well-being.