Question: In chemical engineering, which principle of fluidized bed combustion involves suspending solid particles in an upward$-$flowing gas stream to create a fluid$-$like behavior, commonly applied in efficient and clean energy generation processes?

a$)$ Earth science$-$based fluidization

b$)$ Catalytic$-$based fluidization

c$)$ Mechanical$-$based fluidization

d$)$ Thermal$-$based fluidization