The answer is C: Sweating.
Explanation for each option:
A. Tachycardia - This is a correct sign of hypoglycemia, as low blood sugar can cause an increase in heart rate. However, it is not the most distinctive sign compared to sweating.
B. Polyuria - This is not a sign of hypoglycemia. Polyuria, or frequent urination, is more commonly associated with hyperglycemia (high blood sugar), such as in diabetes.
C. Sweating - This is a classic sign of hypoglycemia. When blood sugar levels drop, the body responds with symptoms like sweating, shakiness, and anxiety.
D. Hot and dry skin - This is not a sign of hypoglycemia. Hot and dry skin is more typically associated with dehydration or hyperglycemia.
In summary, while tachycardia can be a sign of hypoglycemia, sweating is a more direct and common symptom, making option C the best choice.