Which wall type would provide the least resistance to sound transmission in an office setting?

In an office setting, sound transmission is affected by the material and construction of walls. A 9" Concrete Hollow Block (CHB) Wall has less mass and density compared to the other options, which typically results in higher sound transmission. Thinner materials and those with less mass, like the gypsum board, generally allow sound waves to pass through more easily.

The 12" Double Brick Wall provides greater density and mass, which helps in blocking sound effectively. Similarly, a 7" Concrete Wall offers better soundproofing characteristics due to its solid structure, making it denser than the Concrete Hollow Block option. The gypsum board, while not as effective at blocking sound as thicker, denser walls, can still provide some level of sound attenuation but is typically not as resistant as the others in terms of mass.

Thus, the 9" CHB Wall is the one that would provide the least resistance to sound transmission due to its design and material composition, effectively making it the correct choice in this context.