Read this excerpt from Susan Butcher and the Iditarod Trail.

At the head of Kaasen's team was a handsome black dog, Balto. He was not as fast as Togo, but he was strong and steady. Although Seppala used Balto to haul freight, he did not choose him for his relay team. Kaasen had always thought Balto was a brave dog. He would be proved right.

Which clue in the text best helps a reader predict that Balto will play a heroic role in successfully transporting the serum to Nome?

The author states that Kaasen would be proved right.
The author describes Balto as a handsome black dog.
The author points out that Balto was not as fast as Togo.
The author says that Seppala did not choose Balto for his relay team.