What was the codename of the battle that d-day is associated with.

The codename is OVERLORD

Explanation:

The D-Day operation of June 6, 1944 brought together the land, air and sea forces of the allied armies in what became known as the largest invasion force in human history. The operation, given the codename OVERLORD, delivered five naval assault divisions to the beaches of Normandy, France. Hope this helped :)

i think your answer there is c