Find the odd number / letters / word from the given alternative.

The odd one out is kilometres. The other options are all units of mass, while kilometres is a unit of length.

• Tonnes are a unit of mass equal to 1000 kilograms.
• Quintals are a unit of mass equal to 100 kilograms.
• Grams are a unit of mass equal to 0.001 kilograms.
• Kilograms are a unit of mass equal to 1000 grams.