OG13逻辑47，求帮忙分析选项意思

小皮球PAL

Certain genetically modified strains of maize produce a powerful natural insecticide.  The insecticide occurs throughout the plant, including its pollen.  Maize pollen is dispersed by the wind and frequently blows onto milkweed plants that grow near maize fields.  Caterpillars of monarch butterflies feed exclusively on milkweed leaves.  When these caterpillars are fed milkweed leaves dusted with pollen from modified maize plants, they die.  Therefore, by using genetically modified maize, farmers put monarch butterflies at risk.
Which of the following would it be most useful to determine in order to evaluate the argument?
A Whether the natural insecticide is as effective against maize-eating insects as commercial insecticides typically used on maize are
B Whether the pollen of genetically modified maize contains as much insecticide as other parts of these plants
C Whether monarch butterfly caterpillars are actively feeding during the part of the growing season when maize is releasing pollen
D Whether insects that feed on genetically modified maize plants are likely to be killed by insecticide from the plant’s pollen
E Whether any maize-eating insects compete with monarch caterpillars for the leaves of milkweed plants growing near maize fields

错误答案我都可以自己排除了，但是不太明白C的意思。
汉语翻译 蝴蝶丢失玉米释放花粉期间是否频繁的feeding？
这样回答YES 不是支持原文的结论了吗？
我看有人是这么翻译的  蝴蝶在吃叶子的时候叶子上有无花粉？回答YES 也是对文章的支持呀~不明白