Which retail innovation of the 1930s fundamentally changed product packaging design by shifting its primary purpose from protection to marketing and self-selling?

The history of product packaging reflects the evolution of consumer behavior, marketing strategies, and technological innovation. Before the emergence of self-service retail environments, packaging served primarily as protection for goods. Today, it's a critical marketing tool, brand ambassador, and consumer experience touchpoint. This trivia question explores a pivotal moment in retail history that transformed how products are presented and sold to consumers worldwide.

This is a live public trivia poll on AIPolls.Net. Vote and see real-time results.

The introduction of supermarkets with self-service shopping
The invention of cellophane wrapping
The standardization of tin cans for food preservation
The widespread adoption of cardboard boxes for shipping