The statement that best explains the connection between the bartering for lives of loved ones and a central idea of the play is:
Their actions show the ruthlessness of power.
In this passage, Antony and Octavius discuss the fate of Lepidus and the use of his life as a bargaining chip, demonstrating a cold and calculating approach to power. It highlights how the quest for control and dominance in the political landscape leads to a disregard for human life and loyalty, which is a central theme in "The Tragedy of Julius Caesar."