Read the excerpt from heart of a samurai.

the strangers leaped out of their boats and pulled them up on the small beach. by signs, they made it clear the castaways should climb aboard.

the fishermen exchanged frightened glances and whispered to one another, “what about denzo and jusuke? ”

gesturing, manjiro communicated to the strangers about the two men in the cave. denzo and jusuke were retrieved, both of them so weak they had to be carried to the boats. everyone found a place and the sailors shoved off. the two boats rowed away from the island toward an unknown future.

which detail readers infer that the strangers and the fishermen speak different languages?

the fishermen communicate with each other by whispering.
men from both groups communicate with hand signs.
the fishermen are unable to follow the strangers’ directions.
the two groups of men leave the island in different boats.