This task involves asking a question, providing a set of 2 options. You are expected to choose the best answer to the question. The output will be in the form of A or B, corresponding to which option is chosen.

Let me give you an example: Question:Who was the man behind The Chipmunks? ,  Options: [A. David Seville, B. Alvin Seville] 
The answer to this example can be: A
Here is why: David Seville was the man behind the Chipmunks. So, the correct answer is A.

OK. solve this:
Question:What are the only two types of mammal that can lay eggs? ,  Options: [A.platypus B.dog] 
Answer:
A