一个关于指代用法的难题！

3. Fossils of the arm of a sloth found in Puerto Rico in 1991, and dated at 34 million years old, made it the earliest known mammals of the Greater Antilles island.

A sloth found in Puerto Rico in 1991, and dated at 34 million years old, made it the earliest known mammals of

C sloth that was found in Puerto Rico in 1991, was dated at 34 million years old, making this the earliest known mammal of

D sloth, found in Puerto Rico in 1991, have been dated at 34 million years old, making the sloth the earliest known mammal on

E sloth which, found in Puerto Rico in 1991, was dated at 34 million years old, made the sloth the earliset known mammal of

我选Ｄ，答案是Ｃ，但是Ｃ用that was结构不是变成定语从句修饰sloth吗？事实上修饰的应该是化石？如果Ａ OF b结构的词定语从句改优先修饰哪个呢？谢谢！

C肯定错吧,首先 that was 是单数,表示指代sloth,逻辑上错误,肯定是fossils被发现,怎么可能是sloth被发现呢,

还有一个错误就是后面的was dated这里应该用复数形式,因为是fossils of

对于a of b that 的形式,我看到过有修饰a的,也看到过修饰b的,所以我认为在这种情况下不应该把这个作为判断标准,应该用其他方法判断