Why Do Lawmakers Make Speeches on the Senate Floor Even

Why do lawmakers make speeches on the Senate floor even if few of their colleagues are present?

A) The speeches lawmakers deliver have a direct effect on their committee assignments.
B) The sponsors of a bill are required to speak on its behalf regardless of attendance in the chamber.
C) Their statements are placed on the record, which allows the public to see the rationale behind congressional decisions.
D) They hope to appear on C-SPAN, which shows only the member who is speaking, not those in attendance in the chamber.
E) They want speeches to which they can refer to during reelection campaigns.