Have you _____ been to China? ?

The question "Have you _____ been to China?" is structured in a way that calls for a word that fits with the present perfect tense "have you been." In this context, the options provided each have different implications and are used in specific scenarios.

The correct answer is B) ever. This option is used in questions to ask about experiences at any time up until now. When asking if someone has ever been to China, you are inquiring about their experience up to the present moment, regardless of when that experience may have occurred.

In contrast, option A) "never" is used to indicate a negative experience, meaning the person has not been to China at all, thus it would not fit in this question format. Option C) "since" is inappropriate here, as it generally refers to a starting point in time and would not fit grammatically. Lastly, option D) "yet" would typically be used in a negative phrase or in positive sentences with a meaning related to anticipation or expectation, making it unsuitable for this specific question structure.

Therefore, "ever" is the most fitting choice, as it correctly prompts for an account of any possible experience in the person's life related to visiting China.