Which of the following is a unit of power of a lens?

The power of a lens is given by : $\mathrm{P} = \frac{1}{\mathrm{f}}$
Where f is the focal length of the lens.

Unit of power: $\frac{1}{\mathrm{unit} \mathrm{of} \mathrm{focal} \mathrm{length}}$

When the unit of focal length is cm, the unit of power of the lens will be cm^-1.

Therefore, we can say that cm^-1 is a unit of power of the lens.