Final answer:
Stoicism was the most popular school of thought during the Hellenistic era, focusing on virtue, acceptance of fate, and living in accordance with nature.
Step-by-step explanation:
The most popular school of thought during the Hellenistic era was Stoicism. Stoicism was founded by the Greek philosopher Zeno of Citium in the 3rd century BCE. It emphasized the pursuit of virtue, the acceptance of one's fate, and living in accordance with nature.
Learn more about Stoicism in the Hellenistic era