Important of home brainy. com to become a citizen of the united states you must a. file a request form in a federal court. b. be at least 21 years old c. have lived in the united states for at least 6 months , or d. pass an english exam and government test.

Your answer will be A - file for a request form in a federal court.

You can be 18 years of age or older to start the naturalization process. 
You have to either be a permanent resident (which you would have a green card) for 5 years, or you have to show proof you lived for at least "3" months in the state or district you are applying for. You have to be able to read, write, and speak basic English.