OG SC160　教えてください

While some propose to combat widespread illegal copying of computer programs by attempting to change people’s attitudes toward pirating, others <by suggesting reducing software prices to decrease the incentive for pirating, and still others by calling> for the prosecution of those who copy software illegally.

(B) by suggesting the reduction of software prices to decrease the incentive for pirating, and still others call
(C)suggest the reduction of software prices for decreasing the incentive for pirating, and still others by calling
(D)suggest the reduction of software prices to decrease the incentive for pirating, and still others by calling
(E)suggest reducing software prices to decrease the incentive for pirating, and still others are calling

Eが正解ですが、Cの方がpropose, suggest, callのパラレルで正しいと思ったのですがいかがでしょうか。教えてください

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