Concept:Dense population occurs in areas with favourable climate, economic opportunities, and urban development.
Explanation:The northeastern seaboard of the U.S.A. is highly urbanised and industrialised.
It contains major cities such as New York, Boston, and Philadelphia.
This region attracts large populations due to jobs, transport, and services.
By contrast, the equatorial lowlands of South America have thick rainforests and a hot, humid climate.
Northern Canada has extreme cold and poor accessibility.
Western Australia is mostly dry and has limited water supply.
Therefore, these other regions are sparsely populated.
Answer:C. the north eastern seaboard of U.S.A