C. What is the most impactful food development in history? Why?

refrigeration and gmos (this is based on research but it is souly opinion based because it all depends on what you think is the most important. please accept this answer with discretion.)

Explanation:

refrigeration because it helped improve shelflife for food all across the world.

gmos because it saved many crops from complete devastation and saved farmers from endless debt and depression (of money).

i think it's the first one because doctors aren't the ones who get rid of the old needles. most of them time it's not even doctors who give you shots, it's nurses.