Of the three Greek orders, ______(1)______ is the oldest and most stable, ______(2)______ featured elegant columns with capitals of spiraled volutes atop the echinus, and ______(3)______ is known for its decorative capitals and fluted sides.

The Doric order is the oldest and is known for its sturdy, simple design. Ionic capitals have the distinctive spiral-shaped volutes, while Corinthian capitals are especially ornate, often decorated with acanthus leaves; their columns are fluted. These features match choice A: Doric, Ionic, Corinthian.

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