The correct option is (d) Tray
The best explanation: Tray bioreactor is used in group-1 solid state fermentation. In group-1, the aeration is not produced naturally and is effortless. Agitation is also not required and is static. Packed bed bioreactors are used in group-2, rotating drum bioreactor is used in group-3, and stirred-bed bioreactor is used in group-4.