According to the Tourism 2020 Vision, the three leading regions for tourist arrivals include Europe, the Americas, and ____.

The correct response identifies East Asia and the Pacific as one of the three leading regions for tourist arrivals according to the Tourism 2020 Vision. This region has experienced significant growth in tourism due to factors such as economic development, improved infrastructure, and a rising middle class with increased disposable income. Countries in East Asia and the Pacific, such as China, Japan, and Australia, have become major players in attracting international visitors, thus contributing to the tourism industry's global expansion.

The other regions mentioned, while important, do not rank within the top three according to this specific vision. For instance, although Europe historically has been a dominant destination for travelers, and the Americas also draw a vast number of tourists, the distinct recognition of East Asia and the Pacific highlights the emerging trends and growth patterns in global tourism dynamics during that time period.