What is the best explanation for why the United States decided to target Hiroshima?

What is the best explanation for why the United States decided to target Hiroshima?
A. It was a center of communications, military command, and supply point for the Japanese army.
B. It would have few casualties because it was nearly destroyed by previous bombings.
C. It was a religiously and culturally significant city for the Japanese monarchy.
D. It was a city with many family connections to Emperor Hirohito and military leaders.