Finally reaching a decision on an issue that has long been politically charged in the Pacific Northwest, politicians decided to postpone by at least five years an ambitious plan to protect wild salmon and other endangered fish, instead of which they proposed a series of smaller steps, by which they intend to protect the fish.

A. politicians decided to postpone by at least five years an ambitious plan to protect wild salmon and other endangered fish, instead of which they proposed a series of smaller steps, by which they intend
B. politicians decided to postpone by at least five years an ambitious plan to protect wild salmon and other endangered fish, proposing instead a series of smaller steps intended.
C. politicians decided to postpone by at least five years an ambitious plan for protecting wild salmon and other endangered fish, and instead they proposed a series of smaller steps, intending.
D. an ambitious plan to protect wild salmon and other endangered fish was postponed by politicians, who instead proposed a series of smaller steps, intending.
E. an ambitious plan to protect wild salmon and other endangered fish has been postponed by politicians, proposing instead a series of smaller steps intended.

OA: B

I'm confused between C and D. Can any experts help?