The percentage of projects with developed controls on scope creep is the best key performance indicator (KPI) to measure how effectively risk management practices are embedded in the project management office (PMO), as it reflects the ability of the PMO to identify, assess, and respond to the risk of project scope changes that may affect the project objectives, budget, and schedule. The other options are not the best KPIs, as they do not directly measure the effectiveness of risk management practices in the PMO, but rather the outcomes or consequences of risk management decisions. References = CRISC Review Manual, 7th Edition, page 110.