Convectional rainfall occurs when the sun heats the Earth`s surface, causing the air immediately above it to become warm and rise rapidly. As the warm air rises, it cools, and the moisture within it condenses, forming clouds and eventually leading to rainfall.

In the context of the given options, the Amazon basin (option 1) experiences convectional rainfall. The Amazon basin covers a large area of South America, including parts of Brazil, Peru, and several other countries. The region is known for its tropical rainforest and high levels of annual rainfall.

The Amazon basin receives convectional rainfall due to its location near the equator, where the sun`s rays are more direct and intense. The warm and moist air in the region rises rapidly, leading to the formation of enormous thunderstorms and heavy rainfall. This convectional rainfall is vital for the sustenance of the Amazon rainforest, which is one of the most biodiverse regions in the world.

Therefore, the correct answer is option 1, the Amazon basin, as it experiences convectional rainfall due to its proximity to the equator and its role in sustaining the unique ecosystem of the Amazon rainforest.