GWD26-5语法

此题为ＧＷＤ26的ｖｅｒｂａｌ第5题，答案为Ｄ，但我觉得是Ｅ，因为更简洁，且allow sb. to do也对，就是不知so与so that有什么不同用法．请高手指点，谢谢．

The particular design of muscles and bones in the neck and limbs of the turtle allow

that it can draw in its exposed parts such that an attacker can find nothing

but hard shell to bite.

A.     allow that it can draw in its exposed parts such that

B.     allow it to draw in its exposed parts, and so

C.     allows for it to draw in its exposed parts and that

D.     allows that it can draw in its exposed parts, and so

E.      allows it to draw in its exposed parts, so that