Read the excerpt from The Fellowship of the Ring.

"I'm sorry I can't explain it all," answered Frodo. "I am tired and very worried, and it's a long tale. But if you mean to help me, I ought to warn you that you will be in danger as long as I am in your house. These Black Riders: I am not sure, but I think, I fear they come from—"
"They come from Mordor," said Strider in a low voice. "From Mordor, Barliman, if that means anything to you."
"Save us!" cried Mr. Butterbur turning pale; the name evidently was known to him. "That is the worst news that has come to Bree in my time."
"It is,"" said Frodo. "Are you still willing to help me?"
"I am," said Mr. Butterbur. "More than ever. Though I don't know what the likes of me can do against, against—" he faltered.
"Against the Shadow in the East," said Strider quietly.

Which responses accurately explain elements the author uses in the excerpt to reveal the nature of the Black Riders?
(Select all that apply.)

A) The Black Riders are from Mordor.
B) The Black Riders bring danger to anyone who harbors Frodo.
D) Mr. Butterbur is familiar with the name "Mordor" and is frightened by it.
E) Strider refers to the Black Riders as "the Shadow in the East.