In this question, two statements are given. followed by three conclusions labelled I. II and III. You have to consider the statements to be true even if they seem to be at variance with commonly known facts, and decide which of the given conclusions, if any, follow(s) from the given statements.
Statements :
All mansions are palaces.
No castles are palaces.
Conclusions:
I: Some palaces are mansions.
II: Some castles are mansions.
III: No mansions are castles.

Correct option is D

Some palaces are mansions.
· Since all mansions are palaces, it follows that at least some palaces must be mansions. This conclusion is  valid.
Some castles are mansions.
· The statements clearly state that no castles are palaces, and all mansions are palaces. Therefore, castles cannot be mansions. This conclusion is  invalid.
No mansions are castles.
· Since all mansions are palaces and no castles are palaces, it follows that no mansions can be castles. This conclusion is  valid.