Final answer:
In Greek tragedy, the group of Theban elders who comment on the events of the drama and react to its tragic progression is called the Chorus.
Step-by-step explanation:
The correct answer is A. Chorus. In Greek tragedy, the chorus is a group of Theban elders who comment on the events of the drama and react to its tragic progression. They serve as a collective voice representing the citizens of Thebes and provide insight and reflection on the actions of the main characters. The chorus adds depth and emotion to the play and plays an integral role in the overall performance.