Fixed payments not paid as of the commencement date would be included in the measurement of the lease liability at the beginning of the lease term. These are the payments that would be recognized in determining the lease liability upon lease inception.

Fixed payments made before the commencement date would typically have already been accounted for and would not be part of the initial measurement of the lease liability.

All termination penalties included in the lease would only be included in the lease liability's measurement if it is reasonably certain that the lessee will exercise the termination option, and if the lease term reflects this. Variable payments that depend on sales volume are not included in the initial measurement of the lease liability, as they are not fixed amounts and are therefore excluded from the calculation at the lease's inception.

Hence, the correct answer is: Fixed payments not paid as of the commencement date.