Final answer:
The disclosure of Top Secret information could lead to exceptionally grave damage to national security. Top Secret is the highest level of classified information, surpassing Confidential and Secret levels, and relates directly to national defense and crucial operations.
Step-by-step explanation:
The type of information that, if disclosed without authorization, could be expected to cause exceptionally grave damage to our national security is c) Top Secret information. This classification indicates that the information is of the highest sensitivity level within the spectrum of classified information, which also includes Confidential and Secret levels. Unlike Sensitive but Unclassified information, which is protected due to concerns about privacy and other non-national security interests, Top Secret information directly relates to national defense and security concerns. Disclosure of such information could compromise intelligence activities, military operations, or the safety of confidential sources.
A clear example of the gravity of disclosing Top Secret information can be found in historical events like the Pentagon Papers case. The Supreme Court ruled that while certain sensitive information related to troop movements and the names of undercover operatives could be restricted from publication, other parts of the classified study were allowed to be published. This highlights the delicate balance between freedom of expression and ensuring national security.