This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Overactive nodule, which takes up isotope while the surrounding gland does not, is known as: 
Select and explain. 
A. Hot nodule., B. Warm nodule., C. Cold nodule., D. All of the above.
A: Hot nodule.
Answer: A: Hot nodule. 
Explanation: None