Step 1: Identify the relationship in the stem.
A diva is a performer} (not a manager) whose typical domain is opera.
Step 2: Test each option for the same performer$\to$performance-domain link.
(a) producer : theatre} — producer is not the on-stage performer; role mismatch.
(b) director : drama} — director manages a drama; again, not the performer.
(c) thespian : play} — a thespian (actor) is the performer in a play; matches performer$\to$genre/venue.
(d) None of these} — incorrect because (c) fits.
\[
\boxed{\text{(c) thespian : play}}
\]