The answer to your question is C, The choral ode that follws the prologue. I will explain why
The first intervention of the Choir, which usually has between three and six interventions called "stásimos", or parodos, by the name with which the lateral corridors of access to the orchestra were designated, since this first intervention constituted the entrance song of the choir, He was parading until he took his place in the orchestra, admitting the secondary character of the prologue, at the time when the play began with the párodos, in this part the corypheus expounded the theme on which the tragedy would later turn, singing a roll of Anapésticos verses and then the choir burst its lyrical song.