Final answer:
The sculpture Augustus of Prima Porta is made of option 3) marble, reflecting the style of Roman sculptures during his reign and embodying both the political propaganda and idealization of Emperor Augustus.
Step-by-step explanation:
The sculpture of Augustus of Prima Porta is made of marble. This renowned sculpture from the 1st century CE illustrates the Emperor Augustus in a manner that conveys his authority and connections to both divinity and Roman ideologies. Marble became widely popular during the reign of Augustus, who once stated that he 'found Rome a city of brick and left it a city of marble'.
This medium was chosen for its durability and the value it added to the art created throughout his ambitious building campaigns. Modeled after Greek predecessors, specifically resembling the style of Polykleitos' Doryphoros, the Augustus statue embodies both the Roman admiration for Greek art and the political propaganda of the time by idealizing and portraying Augustus with perpetual youth and oratorical prowess.