Answer:
a. moles divide by volume
Step-by-step explanation:
Molarity, denoted by symbol M, refers to the molar concentration of a solution. It is calculated using the formula as follows:
Molarity = number of moles of a solute ÷ volume of the solvent
Since, number of moles (n) has the unit: moles and volume (V) has the standard unit: Litres, then the unit for molarity is moles/litre or M.