The correct answer is - Middle East.
The Kaaba is located in Southwestern Asia, a region also known as the Middle East. More specifically, it is located in Mecca, in the country of Saudi Arabia, which is the birthplace of the Islam.
The Kaaba is in the center of the largest mosque in the world. It is considered to be the most sacred place in the Islam. Every year millions of Muslims visit this huge black rock that is considered sacred while they are on a pilgrimage.
This huge, black stone actually has been a sacred place since ancient times, much earlier than the emergence of the Islam, and its origin is still unknown.