What does this line of dialogue reveal about rainsford’s character?
he is worried that the sailors may be correct about the island.
he is a rational man who is unaffected by superstition.
he is familiar with the island and its mysterious inhabitants.
he is interested in getting more information from the sailors.
"pure imagination," said rainsford. "one superstitious sailor can taint the whole ship's company with his fear."

This line of dialogue shows that Rainsford is a rational man. He does not believe in superstition. He is aware that people in a group may disregard their own decision making and critical thinking facilities in favour of confomity within the group. If a superstitious idea begins to gain traction amongst the men, they may succumb to mass hysteria. Rainsford hopes to calm the fears of the listener by telling them indirectly to disregard their own fears about the island.