Why is A wrong?

Hi Tyler808, The initial argument is as follows: If MA -> KA If KA -> SMB Not all KA are MA THUS: Some SMB are not MA We could anonymize this as follows If x then y If y then Z Not all Y are X Thus: Some Z are not X Let's look at A: If calc then comp If comp then AR Not all AR are calc THUS: some AR are not comp And anonymized If X then y If Y then Z Not all Z are X Thus: not all Z are Y This does not match our initial pattern, the conclusion is different.