All of the above.
Masks in Greek theatre played a crucial role by exaggerating facial expressions, which helped distant viewers interpret the emotions and characters more clearly. They also allowed actors to easily switch between multiple roles, as many performers played more than one character in a single production. Additionally, the masks, often made from materials that could amplify sound, contributed to better acoustics, helping the actors' voices carry across the large outdoor amphitheaters. Thus, masks enhanced performances in multiple ways.