What Is the Difference Between a Broker and a Dealer

What is the difference between a broker and a dealer?

A) There is no difference.
B) The broker takes a position in a transaction while a dealer for a fee merely arranges trades between buyers and sellers.
C) The broker sells stocks and bonds, whereas the dealer only deals in bonds.
D) The dealer sometimes takes a position (becomes a principal) in a transaction, in addition to arranging trades; the broker only arranges trades for a fee.