What is the significance of boxes and galleries in a proscenium theatre?

a
They provide additional performance space and allow actors to engage more directly with the audience.
b
They are the offstage areas on either side of the stage, concealed from the audience's view.
c
They refer to elevated seating areas located on the sides or above the main seating area of the theatre, providing additional seating options and perspectives for the audience.
d
They allow for the use of elaborate set designs and scenery.

c) They refer to elevated seating areas located on the sides or above the main seating area of the theatre, providing additional seating options and perspectives for the audience.