Informal institutions require what type of "supporting pillar (s) ?"

a. Normative and cognitive

b. Regulatory

c. Regulatory and normative

d. Normative

I think the answer is A: normative and cognitive.

The normative pillar is about how the values, beliefs, and actions of other relevant players - collectively known as norms - influence the behavior of focal individuals and firms. And the cognitive pillar is composed by the internalized (or taken-for-granted) values and beliefs that guide individual and firm behavior.