Archeologists believe that the prehistoric monument known as Stonehenge, located in Wiltshire, England and estimated at 4,000 to 5,000 years old, serves as evidence of surprisingly advanced technology of early peoples.

A) at 4,000 to 5,000 years old, serves as evidence of

B) as being 4,000 to 5,000 years old, serve as evidence of

C) that it is 4,000 to 5,000 years old, serves as evidence of what was

D) to be 4,000 to 5,000 years old, serves as evidence of

E) as 4,000 to 5,000 years old, serve as evidence of what was

Updated the OA to D. As Chetan mentioned Correct idiom is estimated to be.
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