Step-by-step explanation:
The density of the material is given by,
Density =

Case 1: Rock
Density =

Density =

Density = 2000

Case 2: Pillow
Density =

Density =

Density = 20

Case 3: Bottle of Soda
Density =

Density =

Density = 1000

Case 4: Load of bread
Density =

Density =

Density = 100

Thus, rock and bottle of soda has maximum density.