The correct answer is: Only I and III follow.
The first statement is “Some pens are books.” This means that there is at least one pen that is also a book. The second statement is “All schools are books.” This means that every school is a book. The third statement is “Some colleges are schools.” This means that there is at least one college that is also a school.
The first conclusion is “Some colleges are pens.” This is not necessarily true. Just because some pens are books and some colleges are schools does not mean that some colleges are pens. For example, all dogs are animals, but not all animals are dogs.
The second conclusion is “Some pens are schools.” This is true. The first statement says that some pens are books, and the second statement says that all books are schools. Therefore, some pens must be schools.
The third conclusion is “Some colleges are books.” This is true. The third statement says that some colleges are schools, and the second statement says that all schools are books. Therefore, some colleges must be books.
Therefore, the only conclusions that follow from the given statements are I and III.