The country, which was admitted to the membership of the United Nations in September 2002, is

Eritrea
East Timor
Andorra
Macedonia

The correct answer is: B. East Timor

East Timor was admitted to the United Nations on 27 September 2002. It is the 191st member state of the United Nations.

Eritrea was admitted to the United Nations on 28 May 1993. It is the 182nd member state of the United Nations.

Andorra was admitted to the United Nations on 28 July 1993. It is the 181st member state of the United Nations.

Macedonia was admitted to the United Nations on 8 April 1993. It is the 180th member state of the United Nations.

East Timor is a country in Southeast Asia. It is located on the eastern half of the island of Timor, which it shares with Indonesia. East Timor has a population of about 1.3 million people. The capital of East Timor is Dili.

East Timor was a Portuguese colony from the 16th century until 1975. After a brief period of independence, it was invaded and occupied by Indonesia from 1975 to 1999. A United Nations-sponsored referendum in 1999 resulted in a vote for independence, and East Timor became an independent country on 20 May 2002.

East Timor is a developing country with a low-income economy. The main sources of income are agriculture, oil and gas, and tourism. East Timor is a member of the Association of Southeast Asian Nations (ASEAN).