The correct answer is C) increased appetite and thirst. The key symptoms of sugar diabetes (also known as diabetes mellitus) are increased thirst, increased urination, and increased appetite. This is because diabetes is characterized by high blood sugar levels, which causes the body to lose fluids and triggers the body's hunger response. The other options are incorrect: A) elevated temperature is not a common symptom of diabetes, B) decreased appetite and thirst would be more indicative of other medical conditions, and D) weight gain is not a universal symptom of diabetes - in fact, unintentional weight loss is often a sign of untreated diabetes.