Answer:
Two consecutive events are dependent if the outcome of the second event depends on the outcome of the first event.
Now, suppose that all the books have the same probability of being drawn, let's look at a single shelf.
we take a book from the first shelf, let's ignore the type of book for now.
Now, if we want to get a second book from that shelf, the probability of getting a fiction book is equal to the quotient between the number of fiction books on the shelf and the total number of shelf.
Now we can see that, if the first book drawn was a fiction book, now there are 5 fiction books and 9 books in total, so:
p = 5/9
if the first book was a non-fiction book, now there are 6 fiction books in the shelf and 9 books in total, so the probability in this case is:
q = 6/9
So you can see that the outcome of the second draw depends on the outcome of the first one (only in the case where we take two books from the same shelf)
Then the pair of dependent events is:
A: because in both cases we choose a book from the same shelf
D: because in both cases we choose a book from the top shelf.