Correct option is A

Conclusion 1. All philosophers are teachers. (False)
This is incorrect because the statement only says that all teachers are philosophers, but it does not say that all philosophers must be teachers. There could be philosophers who are not teachers.
Conclusion 1 does not follow.
Conclusion 2. Some mathematicians are philosophers. (True)
Since all philosophers are mathematicians, this means that at least some mathematicians must be philosophers.
Conclusion 2 follows.
Thus, the correct option is (a) Only conclusion 2 follows.