From the following, choose the set in which names of Secretary-Generals of the UNO are arranged in correct chronological order?
A. U Thant, Kurt Waldheim, Dag Hammarskjoeld, Trygve Lie.
B. Trygve Lie, Dag Hammarskjoeld, U Thant, Kurt Waldheim.
C. Trygve Lie, U Thant , Dag Hammarskjoeld, Kurt Waldheim.
D. U Thant, Dag Hammarskjoeld, Trygve Lie, Kurt Waldheim.
Answer: B