Final answer:
The probability that a randomly selected $15 book is a children's book requires specific data on the number of children's books and total books at that price point, which is not provided. Without it, we cannot calculate the correct probability.
Step-by-step explanation:
The question at hand pertains to the concept of conditional probability within the subject of mathematics. The scenario involves classifying books by various characteristics and finding the probability that a randomly selected book, given a price point of $15, is a children's book. To solve this, one would typically need the total number of books that cost $15 and the number of those that are children's books. The probability is found by dividing the number of $15 children's books by the total number of $15 books.
The calculations or data necessary to provide a precise probability are not given within the excerpts provided. To answer such a question, details are required such as the total number of books costing $15, and how many of them are children's books. Without that information, we cannot accurately calculate the probability.
The four answer choices suggest data points that are not included in the excerpts provided. Therefore, it is impossible to determine the correct answer without additional information about the bookstore's inventory classified by reader group, type of book, and cost. To assist further, one would need access to this specific data.