678.
Television programs developed in conjunction with the marketing of toys, which was once prohibited by federal regulations, are thriving in the free market conditions permitted by the current Federal Communications Commission.(A) Television programs developed in conjunction with the marketing of toys, which was once prohibited by federal regulations, are (B) Television programs developed in conjunction with the marketing of toys, a practice that federal regulations once prohibited, is (C) Developing television programs in conjunction with the marketing of toys, as once prohibited by federal regulations, is (D) Federal regulations once prohibited developing television programs in conjunction with the marketing of toys, but they are (E) Federal regulations once prohibited developing television programs in conjunction with the marketing of toys, but such programs are
答案是E没有问题，谁能仔细分析一下C为什么不对？Developing这个现在分词和后面的is thriving逻辑上能说通嘛？另外，as once prohibited by …这个结构对不对？谢谢 | 
