Select the letter of the correct answer.

Based on the Article, which best replaces the question mark in the box above?

There are two boxes. The box on the left is labeled "Cause," and it has a question mark in it. There is an arrow pointing to a box on the right. The box on the right is labeled "Effect," and it says "Marshmallows were once considered a rare luxury ."
Press enter to interact with the item, and press tab button or down arrow until reaching the Submit button once the item is selectedAMarshmallows were made with expensive ingredients like cornstarch and corn syrup.
BMarshmallow recipes required gelatin, which was produced only in Mesoamerica.
COnly Swiss candlemaker Daniel Peter knew how to get root sap from the marsh mallow plant.
DEach marshmallow had to be individually poured and molded by hand.