Final answer:
The Central Intelligence Agency (CIA) was the U.S. government agency that conducted research with LSD during the 1950s.
Step-by-step explanation:
The correct answer is A) Central Intelligence Agency (CIA). During the 1950s, the CIA conducted research with LSD as part of their efforts in intelligence collection and covert actions during the Cold War. The CIA's role expanded from intelligence gathering to supporting foreign policy through secret political, economic, or military operations.