Who is they in interstellar ?

Who is they in interstellar ?

In Interstellar movie the word "THEY" has some hidden details
In the beginning of the movie
Cooper went to NASA's  secret place and he met scientists

First in NASA launch station scene

Professor Brand:  something send you cooper; they choose you

Cooper: who is "THEY"   (silence)


Second at scientists meeting scene


Cooper: worm holes are not naturally occurring phenomena

Dr.Brand : someone placed it !!

Cooper: "THEY"

And finally at tesseract scene

Tars: "THEY" saved me

Cooper : who the hell is "THEY"  and why they want to help us


So "THEY" represent as  people from future who are living in the fifth dimension here time is represented as a physical dimension (it is also mentioned in this film)

The possiblity is
If dr.Brand (Amelia) gets in to Wolf Edmond's planet as per plan-B there will be a colony of humans
where they are living in higher dimension they can access the 3 dimension space in their 5 dimension reality  they bulit the tesseract inside the black hole

Here cooper can able to communicate with Murphy and cooper send the data to solve the gravity equation
So that the loop will be like that