According to the article, companies that have successfully used the discrimination and fairness paradigm to increase their demographic diversity. a. are usually run by leaders who value due process and equal treatment of all employees
b. are usually run by leaders who have top-down directives
c. to enforce initiatives often have entrenched, easily observable cultures operate in a business environment where there is increased diversity among customers, clients, or the labor pool

a, b and c.

Explanation:

The article in question is the Harvard Business Review article titled Making Differences Matter: A New Paradigm for Managing Diversity  by David A. Thomas and Robin J. Ely.

In this article, the logic that diversity in employment apart from it being  the moral and legal way to do things, is also good for business is explored.

It is shown that companies that have been able to successfully use the discrimination and fairness paradigm to increase their demographic diversity were usually run by effective leaders who valued due process and equality in the treatment of their employees and they had top-down directive issuing power which they used to enforce their view.

The organizations also often have entrenched, easily observable cultures.

reducing the scale of the market for a new product.