To determine why events A (choosing and buying a certain pear) and B (choosing and buying a certain book) are independent, we need to identify statements that correctly indicate that the outcome of event A does not influence the outcome of event B, and vice versa.
The correct statements are:
C. Choosing a certain book does not affect the choice of a pear.
D. Choosing a certain pear does not affect the choice of a book.
These statements indicate that the two events are independent of each other.