The correct answer to this question is option A – Day-Day The term D-day often refers to the day an attack or operation is initiated in military. This term is mostly used to refer to the 6th of June, 1944. It was the day that the Allies invaded Normandy from England during the Second World War. It is believe that the “D” in “D-Day” also stands for “Day” while the French agree that the “D” stands for “Disembarkation”.
Other says “D-Day” stands for Day of Decision”. The day before the D-day is known as “D-1” and the day after the D-Day are known as “D+1” and this goes on. Also, “H-Hour” was used to refer to the start time of the operation. Hope you find this information helpful.