I want to know the answer to the following question:
Ash and hickory are often used for baseball bats to comply with the rules of what organization?
All the background I'm provided with is that "The baseball bats which are legal for use in Major League Baseball are frequently made of ash wood or hickory, and in recent years have been constructed from maple even though that wood is somewhat more fragile.". Is that enough to answer the question?
Answer: yes