GWD-9-27问

Scientists have identified an asteroid, 2000 BF19, that is about half a mile wide and, if it strikes Earth, it can do tremendous damage to part of the planet but probably not cause planetwide destruction.

A

A.      and, if it strikes Earth, it can do tremendous damage to part of the planet but [t1] 

B.      and, if it would strike Earth, part of the planet could experience a tremendous amount of damage but it would

C.      and that, if it were to strike Earth, could do tremendous damage to part of the planet but would

D.      and that, if Earth is struck by it, can do part of the planet tremendous damage, but it would

E.       and that, if it strikes Earth, it could experience a tremendous amount of damage but

翻了前面NN们的讨论，有人排除A的理由是and前面需要加逗号以表示两个句子并列。可是我翻白勇语法，发现可以用“句子1 and 句子2”的。而且我记得og10里面也有相关的例子（可惜开始按关键字找了半天也没有找出）。我去国外的网站上查了下，鬼子也没有说逗号错误的。请牛牛们指点

答案是什么？

我选C

我同意白勇的说法，

用一个逗号就排除，这是只见树叶，不见泰山的做法。