Question: Which German-American pianist, conductor, and composer wrote the score for Katharine Hepburn's only stage musical? 
Sentence (from "Katharine Hepburn performances"): Over the next six decades, she appeared in a range of genres, including screwball comedies, period dramas, and adaptations of works by notable playwrights Tennessee Williams, Eugene O'Neill, and Edward Albee.
Relevant evidence: No