The headquarters of the International Cricket Council (ICC) is located in (B) Dubai, United Arab Emirates. The ICC is the global governing body for the sport of cricket and is responsible for organizing international cricket events, formulating rules, and promoting the game worldwide. The decision to move the headquarters to Dubai was made in 2005, and the ICC officially opened its office in Dubai in 2006.

Downs grasslands, commonly known as "downs," are extensive grassy plains found in Australia. These grasslands are a distinctive feature of the Australian landscape, characterized by vast expanses of open grassy areas. They play a crucial role in supporting unique ecosystems and biodiversity in Australia. Downs are often associated with pastoral activities and are utilized for grazing livestock, especially in regions with a semi-arid to arid climate. These grasslands contribute to the ecological diversity of the Australian continent.

Arakan Yoma is the extension of the Himalayas located in (D) Myanmar. The Arakan Yoma mountain range runs through the western part of Myanmar (Burma) and extends into southeastern Bangladesh.

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).

Tel Aviv is the major city of (B) Israel. It is one of the largest and most populous cities in Israel, located on the country's Mediterranean coastline. Tel Aviv is a vibrant and modern city known for its cultural richness, economic activity, and diverse population. It is a center for technology, innovation, and the arts in the region.

The headquarters of the International Atomic Energy Agency (IAEA) is located in (B) Vienna, Austria. Vienna has been the headquarters of the IAEA since its establishment in 1957. The city's selection as the headquarters reflects its role as a neutral and international city, making it a suitable location for an agency tasked with promoting the peaceful use of nuclear energy and preventing its use for military purposes.

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.