What does Judith Butler mean when she suggests that gender is “performed” ?

What does Judith Butler mean when she suggests that gender is “performed” ?

A. Gender does not reflect an essential truth, but rather is a role people play based on their internalization of socially constructed gender roles.
B. Gender roles do not exist.
C. Real gender roles are scripted by excellent writers.
D. Only individuals who have the capacity to perform have gender.