Answer:
The factor that influences the most in Lars's reading comprehension is d: the reader's interest in the topic.
Step-by-step explanation:
In this particular case, the reader - Lars - is interested in the text from Geography class because he relates himself with the topic. The text is about Sweden and he was born in Sweden, so he already knows some things, but would like to know more about this country. It can be easier for him to understand the topic because that culture isn't rare for him, in a way, he also belongs there and a part of him is from Sweden, so it is easier for him to incorporate new facts and information about a place that he relates to, he also wants to know more and probably pays more attention to it.