Final answer:
The highest percentage of people employed in the tertiary sector is most likely to be found in a large urban area. This is due to the broad range of specialized services offered that are not available in smaller towns or rural settlements.
Step-by-step explanation:
You are most likely to find the highest percentage of people employed in the tertiary sector, such as services and retail, in a large urban area. This sector includes a wide range of services including entertainment, tourism, media, healthcare, financial and legal industries, and education. As economies develop, there's a shift from primary and secondary sectors to the tertiary sector, particularly in well-developed regions like the United States, Japan, and Western Europe. Large cities often provide more specialized and higher order services that are not available in smaller towns and rural areas, such as major league sports or highly specialized boutiques. Consequently, the urban workforce is primarily engaged in these service-based industries.