Final answer:
The architectural order being discussed, known for its unfluted columns and plain decoration, is the Tuscan Order. so, option a is the correct answer.
Step-by-step explanation:
The classical order of Roman origin being described, which is characterized by an unfluted column, and a plain base, capital, and entablature with only moldings as decoration, is the Tuscan Order. While it takes inspiration from the Roman Doric, the Tuscan Order is more simplified and lacks the fluting and decoration that are seen in Doric columns. In contrast, the Corinthian Order is known for its ornate capitals with acanthus leaves, the Ionic Order features volutes in its capitals and bases supporting its columns, and the Composite Order is a combination of Ionic and Corinthian features.
The classical order of Roman origin is the Tuscan Order.
The classical order of Roman origin, characterized by an unfluted column and a plain base, capital, and entablature with no decoration other than moldings, is the Tuscan Order.