What BEST defines roles and responsibilities in relation to process and activities?

A.
Human resource model

B.
Configuration baseline

C.
Service model

D.
RACI matrix

Explanation:
http://www.thecqi.org/Documents/community/South%20Western/Wessex%20Branch/CQI%
20Wessex%20-%20RACI%20approach%207Sep10.pdf (page 9)