What? You have to ask a question! Nothing is being asked or anything.
The correct answer is I and III only.
When you read a text and want to decide what the author's purpose for writing it was, then you need to take a look at the evidence he or she presented, as well as whether or not that evidence was appropriate. What is irrelevant here, however, is how fast or how slow you read the text - that has nothing to do with the author's purpose.
