Which of the following is not an SI unit?

Pound

Explanation:

SI Unit stands for the International Standard of Unit. Thus from the options given, metre is a measure of length which is an SI unit. Kilogram is a measure of mass of a goven matter which is also an SI unit. Second is a measure of time which is an SI unit. Pound is a measure of masswhich is not an SI unit but has to be converted to kilograms which an SI unit.