Statements : No paper is pen. No pen is pencil. All erasers are papers.

Conclusions :
I. Some papers are erasers.
II. No pencil is eraser.
III. No pen is eraser.
IV. All papers are erasers.

I is the converse of the third premise and so it holds.

No paper is pen. No pen is pencil.

Since both the premises are negative, no definite conclusion follows.

All erasers are papers. No paper is pen.

Since both the premises are universal and one premise is negative, the conclusion must be universal negative and should not contain the middle term. So, it follows that 'No eraser is pen'. III is the converse of this conclusion and so it holds.

Hence, only I and III follow.