The correct answer is C - Use class of service. In Kanban, the Class of Service (CoS) model is a key technique for prioritization and flow management. It helps teams decide which work items should be expedited, delayed, or treated as standard. Using CoS enables teams to handle tasks based on urgency, business value, and risk.
From PMI Agile Practice Guide:
"Classes of service define the rules by which work is selected, prioritized, and delivered. They help make prioritization policies explicit and transparent to stakeholders and team members." (PMI Agile Practice Guide, Section 5.4 - Kanban and Flow-Based Approaches) From Mike Griffiths' PMI-ACP Exam Prep Book:
"Class of service models-such as 'Expedite', 'Fixed Delivery Date', 'Standard', or 'Intangible'-allow teams to prioritize tasks by business value, risk, and urgency. This is particularly useful in Kanban systems where items flow continuously." (Mike Griffiths, Chapter 3 - Value-Driven Delivery / Kanban Practices) Option A (involving the product owner) is more applicable to Scrum teams; Kanban teams often have shared ownership of flow.
Option B (reviewing WIP limits) affects flow but doesn't guide task prioritization.
Option D (measuring lead time) helps with process analysis but not immediate prioritization.