Test analysis: "China * * * launched the second batch of the Party's mass line education practice activities from top to bottom" is conducive to maintaining the Party's advanced nature and embodies the Party's purpose of serving the people wholeheartedly, so item C meets the meaning of the question and can be selected; When New China was founded, China established the status of the people being the masters of the country. Item A was incorrectly stated and could not be selected. The party's mass line education practice involves the party's democratic ruling mode, not scientific ruling, so item B is irrelevant and cannot be selected; The party's mass line education practice is not directly related to the improvement of the multi-party cooperation system led by * * *, and item D cannot be selected. So, the answer is C.