Me choose only 1 answer either 1. , 2., 3.

His thesis is carefully explained in one. The paragraphs and pages to follow would be covered by that sentence.

Three is about how Augustus found war to be much more dangerous and much advantageous to Rome and her existence as a formidable empire.

Two is a statement of what happened under the republic and how expansion took place under the republic. It is likely a brief summary of what has been covered although that is a guess.