The collection from which Doug has to select, has 5 poetry books, 3 novels, 4 self-help books and 10 pop-up story books.
From these, Doug has to choose 1 book from each category. Since the order in which he chooses is not important, this is a question on Combinations, therefore, we apply the \(n_c_r\) expression to get our answer.
Number of ways to select 1 poetry book from 5 poetry books = \(5_C_1\) = 5
Number of ways to select 1 novel from 3 novels = \(3_C_1\) = 3
Number of ways to select 1 self-help book from 4 self-help books = \(4_C_1\) = 4
Number of ways to select 1 pop-up story book from 10 pop-up story books = \(10_C_1\) = 10
Since Doug has to select all of them simultaneously, we need to multiply the values as per the Fundamental Principle of counting.
Therefore, number of different selections possible = 5 * 3 * 4 * 10 = 15 * 40 = 600
The correct answer option is D.