The statement which best expresses the central idea of the text is C: The Supreme Court case that protected students' freedom of speech in school continues to be important and relevant to students 50 years later. This can be deducted from sentences such as "What they learnt, among other things, was that history repeats itself, even in their young lives" and "Overall,the kids seemed impressed that this 50-year-old case was relevant to their lives". The overall tone of the comments made by the students in the last paragraph reveal how such an old case can still exert a great influence on our young generation of today; take as an example Soracha McGrath's remark: "Even though it was so long ago, it is still so prevalent today."