What are two appropriate recommendations?

During your RRA assessment of a potential Cisco TelePresence System 3000 room you notices.
*None of the insulated walls extend up to the structural deck above the suspended ceiling tiles.
*All adjacent rooms are conference rooms.
The customer makes it clear that their landlord prohibits wall construction in the open plenum space above the suspended ceiling. What are two appropriate recommendations? (Choose two.)

A.
Recommend the customer doubles the layer of drywall below the plenum ceiling to achieve adequate isolation from adjacent room.

B.
Recommend the customer installs white noise generator to mask the noise from adjacent rooms.

C.
Recommend the customer installs added insulation above the suspended ceiling tiles.

D.
Recommend the customer do noting but be advised of possible noise issues with the adjacent rooms so that proper expectation is set.