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).

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.

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.

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.

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.