GWD1-14 ??????

I can not find any discuss with this question, because it seems my GWD editoin is different with you guys. Can you tell me what edition is my GWD and how can I find the discussion with this question from CD? ---Sorry I cannot type in chinese here...

1-14 Yeasts capable of leavening bread are widespread, and in the many centuries during which the ancient Egyptians made only unleavened bread, such yeasts must frequently have been mixed into bread doughs accidentally.  The Egyptians, however, did not discover leavened bread until about 3000 B.C.  That discovery roughly coincided with the introduction of a wheat variety that was preferable to previous varieties because its edible kernel could be removed from the husk without first toasting the grain.

Which of the following, if true, provides the strongest evidence that the two developments were causally related?

1. Even after the ancient Egyptians discovered leavened bread and the techniques for reliably producing it were well known, unleavened bread continued to be widely consumed.
2. Only when the Egyptians stopped the practice of toasting grain were their stone-lined grain-toasting pits available for baking bread.
3. Heating a wheat kernel destroys its gluten, a protein that must be present in order for yeast to leaven bread dough.
4. The new variety of wheat, which had a more delicate flavor because it was not toasted, was reserved for the consumption of high officials when it first began to be grown.
5. Because the husk of the new variety of wheat was more easily removed, flour made from it required less effort to produce.
   

Answer is C....., can anybody explain it? Thanks!!

前提（事实）1：3000BC，发现用于面包发酵的yeast；在此之前，yeast就混合在于bread doughs中。

前提（事实）2：3000BC，引进新品种小麦，它的edible kernel可以在第一次烘烤之前被移除。

要找两者之间的关联，我们就要找出edible kernel和yeast发酵两者互斥的地方。

C选项： 加热edible kernel破坏一种protein，这种protein可以yeast发酵bread dough。

对于其他选项，都是两个前提只提到了一个，没有起到关联作用。