一般现在时描述自然现象 — 英语选择题

植物园的牌子介绍一种常见现象：有些花白天开放，夜晚合上。哪句话用一般现在时描述了这个自然现象？A. Some flowers opens in the day and closes at night. B. Some flowers open in the day and close at night. C. Some flowers opened in the day and closed at night. D. Some flowers will open in the day and close at night.