Paper lice feed on microscopic spores of a certain fungus that grows primarily in damp areas; when these fungal spores are present on the pages of a book, the paper lice will also ingest the paper comprising the pages unless the paper is treated with insecticide. However, many rare and valuable books are too fragile to be treated with insecticide. Dehumidifying the environment to minimize dampness will allow rare books that cannot be treated with insecticide to be stored without risking damage from paper lice. The argument depends on which of the following assumptions?

A. Paper lice can be prevented from entering an area that is being dehumidified.
B. Treating rare books with insecticide will cause more significant damage than that caused by paper lice.
C. After the fungus has been eliminated, fungal spores do not remain in any significant quantity.
D. It is possible to store rare books in a dry environment without causing the pages to become brittle and crack.
E. No other insects, aside from paper lice, typically feed on the paper used to create books.