Dictation typically refers to the act of someone speaking words aloud so that another person can write them down. In the context of your options, it seems like the question might be looking for a definition related to language usage or composition rather than the act of dictation itself. However, none of the provided options directly define dictation.
If you are referring specifically to a language concept, option B, "The choice and use of words," could be the best fit, as it relates to how one might express thoughts, even though it's not a perfect definition of dictation itself.