The business analyst should ask the team to reprioritize the backlog and work on the item at the top. This is because Kanban is a development model that focuses on continuous delivery and flow of work, rather than fixed iterations or sprints. Kanban uses a visual board that shows the status of work items across different stages, such as backlog, in progress, done, etc. Work items are pulled from one stage to another when there is available capacity or demand, rather than according to a predefined schedule or plan. Reprioritizing the backlog can help the team accommodate the new item and ensure that the most important or urgent work is done first. Asking the team to commit to the work for the next sprint may not be a good option because Kanban does not use sprints or time-boxed iterations. Asking the team to pivot and complete the work immediately may not be a good option because it may disrupt the flow of work or create bottlenecks or waste in Kanban. References:
https://trailhead.salesforce.com/content/learn/modules/salesforce-business-analyst-certification-prep/user-accepta
https://trailhead.salesforce.com/en/content/learn/modules/agile-development-with-scrum