Statements : Some books are pens. No pen is pencil. Conclusions : I. Some pens are books. II. Some pencils are books. III. Some books are not pencils. IV. All pencils are books.

The correct answer is $\boxed{\text{C}}$.

Statement 1: Some books are pens.

Statement 2: No pen is pencil.

Conclusion 1: Some pens are books.

This conclusion follows from Statement 1. If some books are pens, then some pens must be books.

Conclusion 2: Some pencils are books.

This conclusion does not follow from the statements. The fact that some books are pens does not mean that some pencils are books.

Conclusion 3: Some books are not pencils.

This conclusion follows from Statement 2. If no pen is pencil, then some books cannot be pencils.

Conclusion 4: All pencils are books.

This conclusion does not follow from the statements. The fact that no pen is pencil does not mean that all pencils are books.

In summary, only Conclusions 1 and 3 follow from the statements.