复习一般将来时 be going to — 英语选择题

Mike 原计划明早去爬山，但因下雨改变了计划。根据他的决定，下列哪句话正确表达了他的新计划？A. Mike is going to climb the mountain tomorrow morning. B. Mike isn't going to climb the mountain tomorrow morning. C. Mike climbs the mountain every morning. D. Mike climbed the mountain yesterday morning.