ANS:B - tunnel

Refractory bricks are usually dried in a tunnel dryer. Tunnel dryers are commonly used for drying various types of materials, including refractory bricks. In a tunnel dryer, the material to be dried is conveyed through a tunnel-like structure on a conveyor belt or other suitable means. Heat is applied to the material as it moves through the tunnel, allowing for efficient drying. This method ensures uniform drying and facilitates large-scale production of dried materials like refractory bricks.