From statement I: M sits second to the right of O. One of them sits at the extreme ends.
From I, we cannot decide who sits second to the left of O.
From statement II: Only one person sits between O and R.
This statement gives many possibilities.
From II, we cannot decide who sits second to the left of O.
From I and II: M sits second to the right of O. One of them sits at the extreme ends. Only one person sits between O and R.
Using both the statements ‘R’ sits second to the left of O.
Hence, data in both the statements I and II together are necessary to answer the question.