D. One short-story writer depicts Merlin as a common magician, while another writer depicts Merlin as a powerful wizard.
An interpretation is how the director or writer decides to portray a situation or character. In the first three options, the movies, books, and stories all have different topics. These are just facts, not interpretation. Interpretations put your own personal spin, thoughts or ideas into it. In the last option, Merlin's character is interpreted differently. In the first he's described as common, but in the second he's depicted as powerful.
It creates the feeling of mystery. By drawing out or stretching the suspense for the reveal of true identity, the writer is able to tap into the imagination, curiosity and the feeling of the readers as they continue to formulate their own theories and hypothesis to satisfy their curiosity. An effective way in literature to keep readers invested.
I’m taking a guess but I would say, weak: off topic