All theatrical productions require what?

The harpsichord produces sound when

a. a solid felt hammer strikes a metal string b. a solid felt hammer strikes a metal rod c. a quill or plectrum plucks a string d. a quill or plectrum plucks a metal rod e. a metal hammer strikes a metal string

________ introduced George Gershwin's "Rhapsody in Blue" in Aeolian Hall in 1924.

A. Paul Whiteman B. Glen Gray C. Count Basie D. Bob Crosby