确认订单的常用表达 — 国际贸易选择题

卖方收到买方订购1000件棉质T恤的Order No. 512，拟复函确认接受该订单。以下四个句子中，属于确认订单的规范常用表达、语气礼貌且信息完整无歧义的是哪一项？ A. We are pleased to confirm our acceptance of your Order No. 512 for 1,000 cotton T-shirts. B. Your order is fine with us, no problem at all. C. We maybe accept Order No. 512 if the price is still OK. D. Order No. 512 has been thrown into our system for processing.