Franz Kafka was a prominent personality of the 20th century as a:

The correct answer is Novelist. Franz Kafka (1883–1924) was a German‑language novelist and short‑story writer from Prague. He is one of the most influential figures of 20th‑century literature, known for works like The Metamorphosis, The Trial, and The Castle. Among the options:

• Novelist: Correct, as Kafka is widely regarded as a literary icon.
• Architect: Not his profession.
• Painter: Not his profession.
• Musician: Not his profession.

Hence, the correct answer is "Novelist".