Which packaging innovation, introduced during World War II, revolutionized military field rations and later influenced civilian food packaging?

Throughout military history, the packaging of rations has evolved dramatically to meet the unique demands of warfare. From ancient preserved foods to modern MREs (Meals Ready to Eat), packaging design has been crucial for troop sustainability, morale, and combat effectiveness. This trivia question explores a significant packaging innovation that revolutionized how soldiers received nutrition on the battlefield during a pivotal period in military history.

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

The SPAM tin with attached key opener, allowing soldiers to easily access preserved meat without tools
The K-ration waxed paperboard box, which protected food from moisture and chemical contamination
The collapsible canvas food pouch with waterproof liner used by Patton's tank divisions
The vacuum-sealed glass jar system developed for submarine deployment in the Pacific theater