Hi Niki,
Thanks for your question! Answer choices (A) and (C) are very similar, but (C) is a better choice since it parrots the relevant part of the passage almost word-for-word.
This question asks us what Fridja's law says about emotional responses to events. This law states that "emotions are elicited only by events appraised as real, and the intensity of these emotions corresponds to the degree to which these events are appraised as real."
The correct answer choice, (C), uses this exact phrasing: "more or less intense depending on the degree to which the person perceives the event to be real."
By contrast answer choice (A) gets a bit looser with its phrasing, describing emotions as "unpredictable," depending on the perceived reality of the event.
So the main difference between (C) and (A) is "more or less intense" as compared to "unpredictable."
In looking at Fridja's law in the passage, Fridja uses precise, almost mathematical language to describe the expected emotional response to an event. The more "real" an event is perceived to be, the greater the emotional response, and vice versa. An event that is solidly in reality will produce an intense response, and a fictional event will produce a very weak response.
Fridja doesn't say that a person's emotional response will be unpredictable -- she seems pretty confident that her formula works. Given the certainty of her language, the precision in answer choice (C) is the best answer.
If Fridja's law stated something like, "we cannot know how a person will react emotionally to an event," the description of "unpredictable" would be a better fit.
I hope this helps clarify things for you.
Good luck!
Athena