Final answer:
Constipation is the clinical manifestation that is a normal age-related variant in an older adult. Other options such as diarrhea, melena, and anorexia are not considered normal and should be evaluated for underlying conditions. so, option c is the correct answer.
Step-by-step explanation:
The clinical manifestation that a nurse would correlate as a normal age-related variant in an older adult is constipation. As individuals age, their digestive system slows down, which can lead to more frequent constipation. This is a common issue among older adults due to several factors including decreased physical activity, inadequate water and fiber intake, and use of certain medications that may impact bowel function.
Diarrhea, melena (dark, tarry stools indicative of gastrointestinal bleeding), and anorexia (loss of appetite) are not considered normal age-related changes and should be investigated for potential underlying causes. For example, chronic watery diarrhea could indicate an infection like giardia or an inflammatory condition, while anorexia could be a sign of psychological conditions such as anorexia nervosa or physical illnesses that affect appetite.