大全375 请大家看一下看一下吧！～～～

In cold-water habitats, certain invertebrates and fish convert starches into complex carbohydrates called glycerols, in effect manufacturing its own antifreeze.
(A) in effect manufacturing its own antifreeze
(B) effectively manufacturing antifreeze of its own
(C) in effect manufacturing their own antifreeze    

doing结构可以表示伴随（修饰主语），可以表示结果（修饰前面句子）。我觉得加了in effect表明是结果，清楚地表达了doing的作用。
(D) so that they manufacture their own antifreeze
我觉得如果没有逗号，D可能从语法上对（但是they还是会有歧义，是指碳水化合物还是无脊椎动物和鱼）
(E) thus the manufacture of its own antifreeze

选C
不懂C in effect是做什么的？
请问C这里是做结果的伴随状语么？
不选D是因为变成了两句句子么？
我认为完全可以表目的啊，比如OG
El Nino, the periodic abnormal warming of the sea surface off Peru,  is a phenomenon in which changes in the ocean and atmosphere combine to allow the warm water that has accumulated in the western Pacific to flow back to the east.