The correct answer is: A. None is implicit.
The statement “Everybody loves reading adventure stories” does not imply that adventure stories are the only reading material, that nobody loves reading any other material, or that all are literate. It is possible that some people love reading adventure stories, while others love reading other types of stories, or even that some people do not enjoy reading at all. It is also possible that some people are illiterate, and therefore cannot read any type of story.
The statement “Everybody loves reading adventure stories” is a generalization, and as such, it is not always true. There are likely some people who do not love reading adventure stories, and there are likely some people who do not read at all. Therefore, the statement does not imply any of the three assumptions.