[General] It is.

[arjitsharma]

I would like to know how I should say the following.
It is your choice.
= Id is your choice

Should I say "d" insteaf of "t" because the "t" is between two vowel sounds?

 

[emsr2d2]

It depends on what you mean by "should". You will hear some native speakers say "Id" but that doesn't mean you have to emulate them. In a form or exam situation, I recommend sticking to pronouncing "it" as "it".
Are you confusing this with a recent thread on double consonants between vowels?

 

[arjitsharma]

Yes, I am confused because the "t" is between two vowels "i" and "i."

 

[Raymott]

Are you confusing this with a recent thread on double consonants between vowels?

No, he's confusing it with the flap that is used in AmE, in which [t] is pronounced as an alveolar flap [ɾ] and which lately has been described as being a [d].
I agree that students should say [t] until they are living in the US and pick it up naturally. In my experience, a 't' pronounced as a 'd' by a non-native, or non-experienced student just makes them harder to understand.

https://en.wikipedia.org/wiki/Flapping

 

[GoesStation]

In American English the t is reduced to a tongue flap that sounds like a d. As a learner you really don't have to try to reproduce this pronunciation, though knowing the pattern may help you understand speech.