What is the key determinant of who votes in the united states?

To vote in the United States, you have to be an American citizen.

There are other requirements:

-At least 18 years old

-Reside in the US

-Not forbidden from voting (probation, court order, prison, etc)

But, being an American citizen is the key requirement.

d) all choices are correct

in the 1950s, country music came into its own before rock-n-roll took off in the 60s while jazz and classical music continued to innovate