Sailors assigned to USS Donald Cook (DDG 75) take a maintenance and material management exam in the ready room. Donald Cook, an Arleigh Burke-class guided-missile destroyer, forward-deployed to Rota, Spain, is conducting naval operations in the U.S. 6th Fleet area of operations in support of U.S. national security interests in Europe. (U.S. Navy photo by Mass Communication Specialist 2nd Class Karolina A. Oseguera/Released)