The answer is the first one (A): There is reduced sensitivity to circulating insulin.
Explanation for each option:
A. There is reduced sensitivity to circulating insulin. - Correct. As people age, they often develop insulin resistance, meaning their body's cells do not respond as effectively to insulin. This can lead to higher blood sugar levels.
B. Older people eat too many sweets. - Incorrect. While diet can influence blood sugar levels, this statement is a generalization and not a specific physiological reason for increased blood sugar in older adults.
C. There is a decreased reabsorption of glucose by the kidneys. - Incorrect. In fact, the kidneys' ability to reabsorb glucose does not typically decrease with age. If anything, the kidneys may become less efficient overall, but this does not directly cause increased blood sugar levels.
D. A and C - Incorrect. Since C is incorrect, this option is also incorrect.
E. All of the above - Incorrect. Since B and C are incorrect, this option is also incorrect.
Summary:
The increased blood sugar in a non-diabetic older patient is primarily due to reduced sensitivity to circulating insulin.