Final answer:
The statement is true as classified meetings require attendees to have both clearance and need-to-know to ensure national security and the protection of sensitive information.
Step-by-step explanation:
The statement 'All persons in attendance at classified meetings shall possess the requisite clearance and need-to-know for the information to be disclosed' is indeed true.
Classified meetings are designed to handle sensitive information that could potentially harm national security if disclosed to unauthorized individuals.
The Government in Sunshine Act and the Freedom of Information Act (FOIA) both contain provisions for governmental transparency, yet they also include exemptions for situations that require confidentiality for the greater good.
This includes, but is not limited to, national security or foreign policy matters, trade secrets, and issues affecting the operations of businesses and organizations.
These measures ensure that only individuals who have been vetted and deemed trustworthy, who also have a legitimate reason to know such information — the 'need-to-know' — can access it.