理解并遵守课堂规则 — 英语选择题

Read the class rule: Don't run in the hallway(走廊). Which picture/action shows a student following(遵守) this rule? A. Xiao Ming walks slowly in the hallway. B. Xiao Ming runs fast in the hallway. C. Xiao Ming shouts loudly in the hallway. D. Xiao Ming eats an apple in the hallway.