Antiguamente, ¿dónde se escuchaba el son cubano?

a. en las casas
b. en las aldeas
c. en los bares
d. en los puertos y fiestas populares

I want to say it's B but I'm gonna go with D too. 
d. en los puertos y fiestas populares

Right en las aldeas

The Cuban Son is a style of music and dance that originated in Cuba. This rhythm combines the structure and characteristics of Spanish music with Afro-Cuban musical elements and instruments, especially some Bantu music elements. It is currently one of the most influential genres of Latin American music and has given rise to other musical genres such as mambo and salsa.  

Its origins are dated at the beginning of the 20th century, when a large number of former slaves, recently liberated after the abolition of slavery, went to live at the lower-class neighborhoods in Havana (Cuba); numerous workers came from all parts of the country and some rural areas as well, in their search of better living conditions and many of them carried their former traditions.  

It is there where the Cuban Son began to be listened, in the most popular areas of Havana.

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Within the rule of law, the principle relates to the idea that all people and institutions are subject to and accountable to law which is applied and enforced. (change some of these words to avoid plagiarism)