OG第6题解释中的一点疑问

6. In virtually all types of tissue in every animal species, dioxin induces the production of enzymes that are the organism's trying to metabolize, or render harmless. the chemical that is irritating it.fficeffice" />

(A)     trying to metabolize, or render harmless, the chemical that is irritating it

(B)         trying that it metabolize, or render harmless, the . chemical irritant

(C)     attempt to try to metabolize, or render harmless, such a chemical irritant

(D)     attempt to try and metabolize, or render harm­less, the chemical irritating it

(E)         attempt to metabolize, or render harmless, the chemical irritant

Although an "-ing" verb such as trying can sometimes be used as a noun, the phrase the organism's trying to metabolize in A is unidiomatic because trying is used as the object of organism's. In B, trying that it metabolize is ungrammatical. The noun attempt could follow organism's; also, it would parallel the noun enzymes, and parallelism is needed here because the sentence uses the linking verb are to equate enzymes and attempt(be 连接前后的话，前后都要求名词并列，一种并列的形式). In C and D, however, attempt to try is redundant. Choice E, which says attempt to metabolize, is best. The phrase the chemical irritant is also the most concise and precise conclusion for the sentence because it clearly refers to the dioxin mentioned earlier.

parallelism is needed here because the sentence uses the linking verb are to equate enzymes and attempt指的平行结构从来没有听说过，哪位高手能够举个例子让在下看的明白一点？多谢