What is tone in writing?
the protagonist’s point of view
the author’s attitude toward the topic
the setting of a work
the rising action of a work

opens up the story by describing an eerie setting of a valley

Explanation:

In "The Legend of the Sleepy Hollow", the author Washington Irving opens up the story by describing an eerie setting of a valley by using words like "quiet" and "stillness". Irving futher describes how people from nearby towns and villages dread to cross the valley because of numerous superstitions and fear of ghosts and supernatural elements among the people.

Through phrases like "one of the quietest places in the whole world." and "The whole neighborhood abounds with local tales, haunted spots, and twilight superstitions", the author creates fear in his audience.