A Service Level Expectation (SLE) in Kanban provides an agreement or expectation regarding the time it will take to complete a work item. An SLE consists of two main elements:

1.A probability (Option B): This is the likelihood or confidence level (e.g., 85%) that a work item will be completed within the specified period.

2.A period of elapsed days (Option D): This defines the maximum amount of time (e.g., 10 days) expected for a work item to be completed. The combination of these two elements helps set clear expectations and guide planning and forecasting efforts(

Options A (A cost of delay) and C (A forecasted date) are not part of the standard elements defining an SLE. The cost of delay is a concept related to prioritization, and a forecasted date is usually derived from the SLE but is not part of it.