怎么都不明白这道逻辑题的答案...

这GMAT的逻辑题我即使认为完全看懂了,做题也还是错了,而且还不明白
答案的理由是什么,比如这题:

The skulls and pelvic bones of some species of dinosaur whare characteristics with the skulls and pelvic bones of all modern birds. Even though not all dinosaurs have these characteristics,there are scientists who claim that all animals that do have these characteristics are dinosaurs.

If the statements above and the claim of the scientists are true,which of the following must also be true?
A. Birds share more characteristics with dinosaurs than they do with other animals;
B.Some ancient dinosaurs were indistinguishable from modern birds;
C.All animals whose skulls share the characteristics of those of modern birds also have pelvic bones that are similar to those of modern birds
D.Modern birds are dinosaurs
E.All dinosaurs are birds;

请大家猜猜答案

所有跟帖： 

• I guess it is D -lilac09- ♀ (31 bytes) () 12/28/2009 postreply 13:06:55

• 还有别的答案吗,过会再公布答案. -陶陶乐,乐陶陶- ♀ (0 bytes) () 12/28/2009 postreply 14:01:41

• 可惜任大教授不在，俺替你喊一嗓子~~ -lilac09- ♀ (0 bytes) () 12/28/2009 postreply 14:07:33

• My shot is C. -YuGong- ♂ (0 bytes) () 12/28/2009 postreply 14:16:10

• Oops. My guess was D not C. -YuGong- ♂ (0 bytes) () 12/28/2009 postreply 15:03:10

• E! ^v^ -小千...千与千寻- ♀ (0 bytes) () 12/28/2009 postreply 14:58:18

• My answer is also D. -ntotl- ♂ (250 bytes) () 12/28/2009 postreply 15:17:25

• 公布答案 -陶陶乐,乐陶陶- ♀ (189 bytes) () 12/28/2009 postreply 17:24:26

• 咱俩一类人 :) -小千...千与千寻- ♀ (350 bytes) () 12/28/2009 postreply 17:35:52

• 回复：咱俩一类人 :) -陶陶乐,乐陶陶- ♀ (168 bytes) () 12/28/2009 postreply 17:39:56

• 回复：回复：咱俩一类人 :) -小千...千与千寻- ♀ (36 bytes) () 12/28/2009 postreply 17:42:49

• 回复：回复：回复：咱俩一类人 :) -小千...千与千寻- ♀ (428 bytes) () 12/28/2009 postreply 17:51:40

• 回复：回复：回复：回复：咱俩一类人 :) -陶陶乐,乐陶陶- ♀ (433 bytes) () 12/28/2009 postreply 17:58:59

• 回复：回复：回复：回复：回复：咱俩一类人 :) -小千...千与千寻- ♀ (675 bytes) () 12/28/2009 postreply 18:16:28

• 回复：回复：回复：回复：回复：回复：咱俩一类人 :) -陶陶乐,乐陶陶- ♀ (344 bytes) () 12/28/2009 postreply 18:32:06

• 回复：回复：回复：咱俩一类人 :) -陶陶乐,乐陶陶- ♀ (184 bytes) () 12/28/2009 postreply 17:53:02