介绍旅行计划的邮件写作 — 英语选择题

你计划十月一日和家人去西安旅行三天。写邮件向外国朋友 Tom 介绍旅行计划时，下列哪一句最适合作为邮件开头？ A. I am writing to tell you about my travel plan to Xi'an during the National Day holiday. B. Sorry, I can't come to your party next week. C. Xi'an is a very old city with many long walls. D. Please send me some photos of your school soon.