B) Because of Covid.**
They allowed actors to change characters quickly by changing masks without the need for lengthy costume changes. Masks have been used in theatre since ancient times in various cultures for a variety of purposes, including to: enhance or distort the actor's voice; to represent different characters or types; to allow actors to play multiple roles without the need for quick costume changes; to project emotional expressions or states more forcefully to an audience; and to symbolize or embody particular qualities or ideas as part of a dramatic work.