Final answer:
The main theme of the literary work 'Crossroads: A Sad Vaudeville' in the lesson 'The Literature of the Americas' is tragedy.
Step-by-step explanation:
The main theme of the literary work 'Crossroads: A Sad Vaudeville' in the lesson 'The Literature of the Americas' is tragedy. Tragedy is a genre that typically involves serious and sorrowful events that lead to the downfall of the main characters. In this work, the characters are facing a sad situation, which aligns with the definition of tragedy.