The correct answer is: Only conclusion I follows.
The first statement is in the form of “All A are not B.” This is logically equivalent to the statement “No A is B.” The second statement is in the form of “All C are A.” This is logically equivalent to the statement “All C are not B.”
To form a conclusion, we can use the following rule of inference:
If all A are not B, and all C are A, then all C are not B.
In this case, the first statement is “All men are not donkeys.” The second statement is “Rahul is a man.” Therefore, the conclusion is “Rahul is not a donkey.”
Conclusion II, “All men are not Rahul,” does not follow. This is because the second statement does not tell us anything about whether or not Rahul is the only man. It is possible that there are other men who are not Rahul.
Therefore, the only conclusion that follows is conclusion I.