Final answer:
The SI unit for mass is the kilogram. Therefore, the correct option is 5.2 kg.
Step-by-step explanation:
The question is asking about the SI unit of mass. The SI unit of mass is the kilogram (kg). Therefore, the correct option is C: 5.2 kg. This is because 'm³' symbolizes volume, 'lb' indicates weight in the Imperial system, and 'K' represents temperature in Kelvin.
Learn more about SI Units