The correct answer is D. Trygve Lie, U Thant, Dag Hammarskjoeld, Kurt Waldheim.
Trygve Lie was the first Secretary-General of the United Nations, serving from 1946 to 1953. Dag Hammarskjöld was the second Secretary-General, serving from 1953 to 1961. U Thant was the third Secretary-General, serving from 1961 to 1971. Kurt Waldheim was the fourth Secretary-General, serving from 1972 to 1981.
The other options are incorrect because they do not list the Secretary-Generals in the correct chronological order.