The correct option is D Both B and C
To overcome the variations in measurement and exchange of data, one standard system of units was developed. This system is called the International System of Units or the SI System of Units. SI system of Units includes seven fundamental units. When writing the name of the unit, the first letter of the unit should be in the small case, if the unit is not named after the person. For example, the symbol for kilogramme is kg. The symbols of the SI units are always written in the singular form and not in plural form. For example, 10 kilogrammes is written as 10 kg and not 10 kgs. If one has to write the full name of the units, then one can use the plural but the unit should be written and no symbols to be used. For example, it is correct to write 10 kilogrammes.