The Environmental Protection Agency’s proposal to place restrictions on both diesel fuel and diesel engines has sparked a counterattack by the oil industry, saying that the move will exacerbate the nation’s fuel supply problems.

A.      on both diesel fuel and diesel engines has sparked a counterattack by the oil industry, saying

B.     on both diesel fuel and engines have sparked the oil industry to counterattack, and they say

C.     on both diesel fuel and diesel engines has sparked a counterattack by the oil industry, which says

D.     both on diesel fuel and engines has sparked the oil industry to a counterattack, saying

E.     both on diesel fuel and diesel engines have sparked the oil industry to counterattack, and it says

 答案是Ｃ，我选Ａ了，觉得更简洁而且还是伴随的，没什么大错啊．．．ＮＮ看看，怎么想的呢＞？

 答案是Ｃ，我选Ａ了，觉得更简洁而且还是伴随的，没什么大错啊．．．ＮＮ看看，怎么想的呢＞？

The Environmental Protection Agency’s proposal to place restrictions on both diesel fuel and diesel engines has sparked a counterattack by the oil industry, saying that the move will exacerbate the nation’s fuel supply problems.

proposal ...  has sparked a counterattack by the oil industry,  -ing phrase.

For A,  the logic  Subjective  for  -ing phrase  is "proposal".   However, the actual meaning in the sentence is the oil industry say.