Prologue - the entrance to the plot.
I think that the first element is prologue.
Prologue is the correct answer.
First, it is important to remember the five parts that compound a Greek drama, which are prologue, parados, episode, stasimon, and exodus. For this question, the one that matters is prologue, which refers to the first scene that helps set the tone and the background of the drama. Due to this, this is the correct answer.
the exodus will come last in greek drama