What is the name of the foremost Argentinian and Uruguayan urban popular song and dance?

The foremost Argentinian and Uruguayan urban popular song and dance is indeed known as Tango. This genre originated in the late 19th century and is characterized by its rich musical elements combined with passionate dance movements. It embodies a fusion of various influences, including African, Indigenous, and European musical traditions, particularly those brought by immigrants to the urban centers of Buenos Aires and Montevideo.

Tango is not only a dance but also a cultural expression that reflects the historical and social environments of Argentina and Uruguay. Its significance is underscored by its recognition as part of the Intangible Cultural Heritage of Humanity by UNESCO. The dance features intricate footwork, close embraces, and improvisation, making it a captivating art form.

The other genres listed do not share the same historical and cultural significance in the context of Argentina and Uruguay's urban music scene. Cumbia, while popular in Latin America, originates from Colombia and has different musical roots. Reggae is primarily associated with Jamaica and has a distinct sound and cultural background. Foxtrot is a ballroom dance that originates from the United States and does not pertain to the urban popular music traditions of Argentina or Uruguay.