When did Japan surrender?

Aafter the first atomic bomb was dropped
Bthe day the Soviet Union invaded Manchuria
Cthe day after Germany and Italy surrendered
Da few days after the second atomic bomb was dropped

Verified Answer :

The correct answer is the last one: D. a few days after the second atomic bomb was dropped. this had to do with the insistence of the Emperor Hirohito. The second bomb was dropped on the 8th of August and surrender was announced on the 15th of August. 

I was just wahing to movie "Unbroken" so the answer is D.