The Sargasso Sea, located entirely within the Atlantic Ocean, is the only sea without a land boundary.

The five oceans from smallest to largest are: the Arctic, Southern, Indian, Atlantic and Pacific.

Auckland, city, north-central North Island, New Zealand. The country's most populous city and its largest port, Auckland occupies a narrow isthmus between Waitematā Harbour of Hauraki Gulf/Tīkapa Moana (east) and Manukau Harbour (southwest).

The smallest continent is Australia. Therefore, the correct answer is (A) Australia. Australia is both a country and a continent, and it is often referred to as the "smallest continent" due to its relatively small landmass compared to other continents.

The longest river in the world is the Nile. Therefore, the correct answer is (D) Neil (Nile). The Nile River is a major north-flowing river in northeastern Africa and is generally considered the longest river globally, with a length of approximately 6,650 kilometers (4,130 miles).