Concept:
The film Utsav (1984) is a classic example of a literary adaptation where a modern director brings a 2,000-year-old Sanskrit play to a cinematic audience.
Step 1: Verifying the director.
The assertion is true. Girish Karnad, the legendary playwright and director, directed Utsav, produced by Shashi Kapoor.
Step 2: Verifying the source material and cast.
The reason is also true. The film is a faithful adaptation of Shudrak's Mricchkatikam (The Little Clay Cart). It correctly identifies Rekha as the courtesan Vasantsena and Shekhar Suman (in his debut) as the impoverished Brahmin Charudatt. This reason explains what the movie Utsav is and why it was a significant directorial project for Karnad.