Why does Gandalf say he would like to melt all the butter out of Barliman Butterbur?
A.
Butterbur forgot to send the letter that Gandalf had given him.
B.
Butterbur revealed Mr. Underhill's true identity to the other guests at his inn.
C.
Butterbur did not allow the hobbits to stay at his inn.
D.
Butterbur let the hobbits' ponies wander off.