Is the OA D. Here we can observe splits "one" and "among", "support of" and "support from", "first of Britain's" and "Britain's first". I would say "among", "support from" and Britain's first" are correct.Also "to seek" is parallel to "to increase". So A B and E are out of the race.

Now on to C and D.As for the reasons stated above D wins.Now onto your question.

The militia seeked "support from" the government.Here it implies that "to survive or to flourish the militia needs the government.

The politician said that he has the "support of" the people. Here it means "morally".

Hope it is clear.

Another one-T

@ Rahul and Ani, remember you had asked me about "parallelism" from right to left". Ron has answered it here.

https://www.beatthegmat.com/monkfish-t270317.html. Sorry to intrude like this.

Thanks Vinay, you are super agile and that's what we need in this forum...
Thanks for the answers and pointers.

ani781 wrote:Thanks Vinay, you are super agile and that's what we need in this forum...
Thanks for the answers and pointers.

I am just doing what i am ought to do. helping...!!!and you are welcome

it is D
one can see that the right part of the sentence contain "to increase income by increasing attendence" for he sake of parallelism, one need to put "to seek" in the underline portion of he sentence. so it must be C or D
"support from" is the right idiom for this construction as the museum is seeking support from X and Y. so D is the right option.
using "among" because we are talking about all the museum of Britian and Victoria and Albert are among those museums.