Correct option is D
The sentence with no error is (d) "The psychologists who are a major part of the investigation interviewed the witnesses."
Explanation: The sentence correctly uses "psychologists," "investigation," and "witnesses" without any spelling errors.
· "Psychologists" (मनोवैज्ञानिक) – Professionals who study the mind and behavior.
· "Investigation" (जाँच) – A formal examination of facts.
· "Witnesses" (गवाह) – People who see an event occur.
Example: "The psychologists who are a major part of the investigation interviewed the witnesses."