Thirteen states from all regions of the country announced a plan to impose new controls on pollution from truck and bus engines in that they will jointly adopt eission limits that would be far stricter than the federal rules.
A to impose new controls on pollution from truck and bus engines in that they will jointly adopt
B to impose new controls on truck and bus engines' pollution by the joint adoption of
C to impose new controls on pollution from truck and bus engines, and jointly adopting
D for imposing new ontrols on pollusion from truck and bus engines, and jointly adopting
E for imposing new controls on truck and bus engine pollution in the joint adoption of

I eliminated BDE quickly, but really got confused while facing the choice between A and C.
I thought they have differnt meanings so I went for A. Do "in that they will jointly adopt" in A and "by jointly adopting" in C have the same meaning?
The "they" in A might be obscure, but I got a sentence, which I thought was where this question come from, from the New York Times:

Thirteen states from all regions of the country will try to impose new national controls on pollution from truck and bus engines on Monday, when they announce a plan to jointly adopt emission limits that would be far stricter than the federal rules.

There was a "they" there. Was it a bad usage that lead to obscure indication?

Thanx

I can't differ them either!
Could anyone give me an explaination?

what is the OA?

also, are you sure all the answer choices have been transcribed correctly? i don't terribly like any of them.