Answer: Option (b) is the correct answer.
Explanation:
We know that density is defined as mass divided by volume of the substance.
Mathematically, Density = 
It is given that density of given cylinder is 75.0 g/ml and its volume is 12 ml. Therefore, calculate its mass as follows.
Density = 
75.0 g/ml =
mass = 900 g
Thus, we can conclude mass of a steel cylinder is 900 g.