The correct answer is A. an aerial photograph that shows the Soviet Union’s missile sites in Cuba
Explanation
The fragment of the question speaks specifically about the missile crisis between the Soviet Union and the United States when the European country secretly established missiles on the island of Cuba between 1958-1962. According to the above, the resource that would best help readers to understand the fragment would be A. An aerial photograph that shows the Soviet Union's missile sites in Cuba because would complement the information in the fragment and give it more complete and accurate information. to readers.