This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Thorax, Subject name: Anatomy
Coronary sinus opens into: 
Select and explain. 
A. IVC, B. Right atrium, C. Left atrium, D. Great cardiac vein
B: Right atrium
Answer: B: Right atrium 
Explanation: B - B.D. Chaurasia, Vol.l 4,h ed, p. 251