Read the sentence from the section "How Can You Find A Theme In Books?"

Finding the theme of a book can be difficult because themes are not stated by the author.

What does this sentence show that other sentences in the section do not?

A
that it is not always easy to find the theme of a book
B
that the author does not write what the theme of a book is
C
that the reader has to find out the theme of a book
D
that finding the theme of a book takes many steps

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