2008年全国人民共向四川地震灾区捐款约43681000000元，这笔款额用科学计数法表示（保留三个有效数字）正确的是[ ]

A.0.437×10¹¹

B.4.4×10¹⁰

C.4.37×10¹⁰

D.43.7×10⁹

Mrs. Green took up the story at the point ____the thief had just made off with the jewels.

A．where

B．which

C．as

D．when