Apart from Bertolt Brecht others who have influenced Epic theatre are:

The correct option is Erwin Piscator and Max Reinhardt.

Erwin Piscator (1893-1966):
Erwin Piscator was a German theatre director and producer who, along with Bertolt Brecht, was a key pioneer of Epic Theatre. Piscator was instrumental in developing the concept of political and documentary theatre. He introduced innovative staging techniques, such as the integration of film projections, socio-political commentary, mechanical stages, and scaffolding. These methods directly influenced Brecht's formulation of the Epic Theatre form and the alienation effect (Verfremdungseffekt).

Max Reinhardt (1873-1943):
Max Reinhardt was a legendary Austrian theatre director and producer who revolutionized modern stagecraft. He is known for his large-scale, spectacular productions, creative use of lighting, and breaking down the barriers between the actors and the audience. Early in his career, Bertolt Brecht worked as an assistant director under Reinhardt in Berlin. This experience exposed Brecht to Reinhardt's epic theatrical scale and creative space manipulations, which helped shape Brecht's future ideas on how theatre could be structured and staged.