Members Sometimes Give a Floor Speech After Introducing a Bill

Members sometimes give a floor speech after introducing a bill. What purpose does this speech serve?

A) It allows the member to call their own panel of witnesses if the bill is brought up in committee
B) It signals the member is serious about the bill and increases its chance of passage
C) It is required by rules in both chambers before a bill can become law
D) It is an opportunity to partner with party leaders to politicize the bill introduction process