Direction: In the following question, the sentence is completed by oneof the choices given below. Mark that choice which best completes the sentence.
Scientists often say that the answer to the prosperity and happinessof life on earth.

A

It is not politicians or economists but that they have

B

It is not politicians or economists but they have

C

They and not politicians or economistsh

D

it is not politicians or economists but it is they who have