Aunit salary planin Workday is specifically designed to support compensation that varies based on ameasurable unit of output, such as miles driven, items produced, or— in this case—kilometers flown. This plan type allows compensation to scale proportionally with the quantity of units, making it ideal for roles where pay increases directly with activity or performance volume.

For airplane pilots, compensation based on kilometers flown is not a fixed allowance or a one-time payment. Instead, it representsvariable earnings tied to ongoing work output, which aligns exactly with the purpose of a unit salary plan. Workday allows administrators to define arate per unit, and the system can calculate estimated compensation by multiplying the rate by the expected number of units. This calculated amount can then be displayed in offer letters, providing transparency and clarity to candidates.

Aperiod salary planis used for fixed salaries distributed over defined pay periods and cannot model variable, unit-driven earnings. Aone-time payment planis intended for bonuses or ad-hoc payments and does not support ongoing estimation. Aunit-based allowance planis typically used for reimbursements or allowances, not base compensation tied to work output.

Therefore, theunit salary planis the correct choice for modeling and presenting estimated wages based on kilometers flown, making option B the correct answer.