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
If a patient with Raynaud's disease immerses his hand in cold water, the hand will: 
Select and explain. 
A. Turn white, B. Become red, C. Become blue, D. Remain unchanged
A: Turn white
Answer: A: Turn white 
Explanation: When a patient with Raynaud's disease immerses his hand in cold water, the hand will turn white. Raynaud's phenomenon is characterized by episodic digital ischemia, manifested clinically by sequential development of digital blanching, cyanosis, and rubor of the fingers or toes after cold exposure and subsequent rewarming. Ref: Harrison's Principles of Internal Medicine, 18th Edition, Page 2071.