Which of the following characteristics was required to be a citizen of Athens

The system of democratic government that began to develop in the first decade of the 5th century B. C. in the Ancient Greek city-state of Athens was a direct, rather than representative, democracy, and every adult male citizen could participate. An assembly of citizens and a council, or boule, met on an almost weekly basis and was responsible for deciding upon the civic and foreign policy affairs of the city-state. Not only were Athens' citizens encouraged to participate in the assembly meetings, those who did not participate were often ridiculed for their lack of involvement.