Plz grade my art and be truthful

Which of these is a consistent periodic pulse separated into equivalent intervals of time?

What role do background vocalists play? a. they provide additional support to the main vocalist and other members of a music group during recording sessions and live events. b. they perform as part of orchestras working for music theaters. c. they mix different songs or music scores and present a unique blend of music to an audience. d. they assemble and organize musical compositions according to their clients’ requirements.

Which is an example of stage directions? (turns out the lights) justin: we are never going to get there! "when are we leaving? " asked ty. list of characters