Which of the following is the most decorative of the classical Greek architectural styles?

The most decorative of the classical Greek architectural styles is indeed the Corinthian order. This style is characterized by its elaborate capitals that often feature an intricate design with acanthus leaves and scrolls, reflecting a high level of artistic detail and ornamental richness. The Corinthian order emerged later than the Doric and Ionic styles, which are more austere and simple in their design.

The Corinthian order is not only visually striking, but it also symbolizes the grandeur and sophistication of the architecture that flourished in the Hellenistic period and later Roman architecture. Its use in monumental buildings often conveyed a sense of opulence and was favored in more decorative contexts, such as during the Roman Empire where it became very popular.

In contrast, the Doric order is the simplest and most robust of the three, emphasizing structural strength, while the Ionic order offers a bit more decorative flair with its volutes (scroll-like ornaments) slightly more embellished than the Doric order but still not as elaborate as the Corinthian. The term "Simple order" is not recognized as a classical style and therefore does not pertain to the established hierarchies of Greek architectural orders.