I would say driver, as the other ones work from offices and desks
Genius: A genius is showing great intelligence skill in a particular area of activity. For example, a mathematical genius.
Gifted: Having outstanding talent. For example, a gifted dancer.
Prodigy: A young person who is unusually intelligent for their age. For example, a child prodigy on the piano.
Savant: a person with great knowledge in a particular subject for example, a computer savant.
On the fourth day, while exploring the island, Huck is delighted to find Jim, who at first thinks Huck is a ghost. Huck is pleased that he will not be alone on the island but shocked when Jim explains that he has run away.
1-2 sentences should be enough.