Which of the Following Differentiates Securities Firms from Investment Banks

Which of the following differentiates securities firms from investment banks?

A) Securities firms are concerned with the commercial side of the business while investment banks are concerned with the retail side of the business.
B) Securities firms assist in trading of existing securities while investment banks specialize in underwriting new securities.
C) Securities firms underwrite new issues of securities while investment banks provide brokerage services.
D) Securities firms originate new issues of securities and investment banks underwrite the securities.
E) Securities firms are concerned with private placements of securities whereas investment banks are concerned with publicly traded securities.