自从2017年2月27日，韩国乐天集团决定为美国“萨德”系统提供基地后，中国人的抗议之声便一浪高过一浪。“萨德”是当今世界上唯一能在大气层内外拦截弹道导弹的地基系统，它不仅是“盾牌”，还能摄取情报和监控对手。由此推测，“萨德”系统的信息传播媒介是（    ）

    On the first day of school, the Nottingham School asked more than 50 students to go home, because the students didn't wear the right clothes. The headteacher said it was an important life lesson for children, though some parents didn't think so.

    In fact, on their first day back from the summer holidays, about 100 students didn't wear the right clothes, so the teachers asked them to stay outside the classroom on the first day. The school made calls to the parents, and 56% of the students went home to change their clothes.

    The Nottingham School started to make its students wear the right clothes in 2013. The headteacher, Dave Hooker said, “Wearing the right clothes, at school or work, is an important lesson for their lives.”

根据短文内容，故答案选择正确答案。