Final answer:
Mark Twain's youngest daughter with whom he had a strong bond was named Jean.
Step-by-step explanation:
The name of Mark Twain's youngest daughter, with whom he had a strong bond, is Jean. Samuel Langhorne Clemens, better known by his pen name Mark Twain, had four children with his wife Olivia Langdon. Their three daughters were named Susy, Clara, and Jean. Of his daughters, Twain shared a particularly close relationship with his daughter Jean before her untimely death at a young age. It's worth noting that Twain's life and relationships with his children have affected his writing and are occasionally referenced in biographical studies of his work.