Why was Okinawa the last step in the Allies' island-hopping campaign? A. It was considered part of the Japanese mainland
B. Japan lacked the resources to occupy other Pacific islands.
C. The atomic bombs were dropped before the campaign ended
D. It was the staging area for the invasion of Japan.​

Because it was the staging area for the invasion of Japan

Explanation:

Answer is D.

D. It was the staging area for the invasion of Japan.

Explanation:

Okinawa was considered one of Japan's native islands, and the conquest of Okinawa dealt a huge blow to the morale of Japan. The objectives for the conquest of Okinawa (other then the morale one), was to obtain the airstrip that was on the island, which in turn would give a much more closer alternative for stricken aircrafts to land at, which greatly saved not only the amount of airmen who would have have to ditch at sea, but also damaged aircrafts.

Finally, before the US pursuit the plan to use the atomic bombs, they had in place, called Operation Down-fall. Operation Downfall called for hundreds of thousands of US and allied soldiers to storm the beaches of Japan and to fight each individual Japanese resident (who remember, because of their bushido code, would initiate a fight to the death or sui-cide order), which would result in heavy casualties. Therefore, in an effort to deter any more casualties, the US nuked first Hiroshima, and then following that, Nagasaki, which deterred the Japanese government enough to surrender, resulting in Operation Downfall not being needed. As a result, Okinawa would be the last step of te Allies island-hopping campaign.

the answer is true sir