Which explicit statement of an authors purpose for writing is an example of a persuasive approach?

The correct answer is A. "This book should motivate every person who cares about freedom to become more involved in government."

With this statement, the author's intention is obviously to persuade us to read the book. It doesn't communicate what was the author's goal (such as statements B and C). It is more persuasive than the statement D because it includes the "who cares about freedom" part, as an appeal to ethos (morals). It's been trying to say that if you don't read this book, it means you don't care about freedom.