Final answer:
A rabbeted joint grid is a metal grid designed for supporting acoustical tiles in a suspended ceiling. It has rabbeted joints that provide a strong and stable connection between the grid and the tiles.
Step-by-step explanation:
The correct answer is d) Rabbeted joint grid. A rabbeted joint is a type of joint where one piece of material is notched to fit into a groove or channel on another piece of material. In the case of a suspended ceiling, a rabbeted joint grid is specifically designed with rabbeted joints to securely hold and support acoustical tiles in place.
The rabbeted joints provide a strong and stable connection between the metal grid and the acoustical tiles, ensuring they stay in position.