Which of these clothing innovations was developed during WWI?

Here is the question :

WHICH OF THESE CLOTHING INNOVATIONS WAS DEVELOPED DURING WWI?

Here is the option for the question :

• Velcro
• Zipper
• Digital watch
• Sunglasses

The Answer:

And, the answer for the the question is :

Explanation:

[STC0012015]. Although the zipper wasn’t invented until after World War I, the B.F. Goodrich Company popularized the term “zipper” in 1923. The U.S. Army issued an order for zippers to be used with money belts to store accessories because at the time, army uniforms lacked pockets. Although buttons were still the norm for attaching uniforms, zippers were gradually integrated into the flight suits worn by military pilots beginning in the 1920s.