To which country did the first Secretary-General of the UN belong?

The correct answer is: A. Austria

Trygve Lie was the first Secretary-General of the United Nations. He was born in Oslo, Norway, on 16 July 1896. He studied law at the University of Oslo and then worked as a journalist. In 1922, he was elected to the Norwegian Parliament. He served as Minister of Foreign Affairs from 1935 to 1940. During World War II, he was a member of the Norwegian government-in-exile in London. In 1946, he was elected Secretary-General of the United Nations. He served in that position until 1952.

The other options are incorrect because they are not the countries of the first Secretary-General of the United Nations.