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: Dental
Female presents with history of color change from pallor to cyanosis on exposure to cold in fingers. This condition is mostly associated with ? 
Select and explain. 
A. Scleroderma, B. Leukemia, C. Lung infections, D. Hepatosplenomegaly
A: Scleroderma
Answer: A: Scleroderma 
Explanation: History of color change from pallor to cynosis on cold exposure suggests raynaud's phenomenon. Raynaud's phenomenon is the most common and earliest manifestation of generalized scleroderma (systemic sclerosis).