Final answer:
The most plausible nursing diagnosis for a patient with a colostomy due to colon cancer treatment is Risk for Excess Fluid Volume Related to Dietary Changes and Changes In Absorption.
Step-by-step explanation:
The most plausible nursing diagnosis for a patient whose treatment for colon cancer has necessitated a colostomy would be option C: Risk for Excess Fluid Volume Related to Dietary Changes and Changes In Absorption.
When a patient undergoes a colostomy, there are changes in the digestive system and absorption of nutrients. These changes can result in an increased risk of fluid volume excess due to dietary changes and altered absorption. The nurse should monitor the patient's fluid intake, assess for signs of fluid overload such as edema or shortness of breath, and educate the patient about dietary modifications to control fluid volume.