This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Transplantation, Subject name: Surgery
Xeno transplantation of heart in human being, which of the animal heart has been used? 
Select and explain. 
A. Pig, B. Horse, C. Dog, D. Rabbit
A: Pig
Answer: A: Pig 
Explanation: Ans. (a) PigRef: Internet Source* Xeno transplant of Piglet heart is tried and has shown successful survival in humans for 200 days.* Pigs were chosen because their anatomy is more or less same like human anatomy.