据中国旅游研究院最新统计数据显示，今年中秋节国庆节8天假日期间，全国共接待游客4.25亿人次，实现旅游收入2105亿元，将旅游收入2105亿元用科学记数法表示为（　　）

A．2.105×10¹¹元

B．2.105×10¹²元

C．2.105×10¹⁰元

D．2.105×10⁸元

If a ship station relays a DSC distress call to an appropriate coast station, it means that（）.

A.the ship has received the DSC distress call on a HF frequency

B.the coast station concerned has not acknowledged it within 5 minutes

C.the ship will take command of search and rescue in 5 minutes

D.A and B