Final answer:
Clara Schumann was taught by her father Friedrich Wieck and her future husband, Robert Schumann, who played a significant role in her musical career.
Step-by-step explanation:
The teacher of Clara Schumann was neither Ludwig van Beethoven, Johann Sebastian Bach, Franz Liszt, nor Wolfgang Amadeus Mozart. She was taught by her father, Friedrich Wieck, who was a well-known piano teacher at the time, but most importantly, Clara Schumann's teacher and mentor was her future husband, Robert Schumann. Although not one of the answer choices provided, Robert Schumann played a significant role in her musical career, both as a mentor and a collaborator.