What Are 'Critical Success Factors

What are 'critical success factors'?

A) They are the competencies that enable an organisation to outperform others in the same environment.
B) They represent the secrets of success that an organisation tries to hide from rivals.
C) They are the organisations major strengths, deriving from the way it deploys its resources.
D) They are those product features that are particularly valued by customers and where the organisation must excel to outperform competition.