No matter when it is written literature becomes memorable when it has a. unique characters or themes b. emotional and passionate language c. a topic that is interesting or d. a message that elicits a response

The correct answer would be D, A message that elicits a response.

Explanation:

When we read a literature, there are many things that make it memorable. Characters in the literature, story of the literature, emotional and passionate language used in it also make it memorable. But the thing that makes it last longer in the memories of a person is the message inside the literature that makes a person to generate a response. For example, if there is a literature about the global warming and that literature gives a message of how important the plantation of trees is, then this message in the literature will provoke the person to elicit a response of planting trees. After reading the literature, when the person will plant the trees, that literature would become more memorable to him. So a literature having a message that elicits a response will be more memorable to a person.

i think it may be b, i'm not exactly too sure on this. but b seems to make more sense.