Liter
The SI unit of measure for volume is the 'Litre'.
You would use Volume.
mililiter
milliliter
millilitres
you would use centimetres to measure the volume for a slice of bread
You would typically use liters or gallons to measure the volume of a hot tub.
Mass divided by Volume!!
Litres.
The basic unit of volume is the cubic metre. In everyday use, the litre is more common.
I suggest you use liters.
You would use liters (L) to measure the volume of a soda container in the metric system.