In the case, Tinker vs. Des Moines, the problem was that the Tinker kids were A. Disrupting the learning environment at school
B. always late for school
C. suspended for wearing black arm bands to protest the Vietnam war
D. attempting to burn an American flag to protest the Vietnam war

The answer would be C.

Explanation:

The reasoning why they went to court was because they argued that their First Amendment right to freedom of speech was being taken away. Tinker argued that they weren't doing any harm to anybody by wearing the arm bans and it was their right to do so, because of the First Amendment. The court ruled in favor of Tinker in end.