Final answer:
The option that is NOT a feature of a typical 19th century Italian aria is 'Simple and straightforward structure'. 19th century Italian arias are known for their elaborate melodies, dramatic expression, and intricate orchestration, aligning with the Romantic era's stylistic tendencies.
Step-by-step explanation:
The feature that is NOT typical of a 19th century Italian aria is 3) Simple and straightforward structure. A typical Italian opera aria from the 19th century is characterized by ornate vocal melodies and dramatic and emotional expression, often with elaborate orchestration. These elements reflect the Romantic era's emphasis on heightened emotion and complexity in musical composition. In contrast, a simple and straightforward structure was more often found in earlier periods, such as the Classical era, where composers valued clarity and formality over the Romantic era's extravagance and emotional depth.