Choosing a qualified CEO to run a corporation

There are many qualities necessary to be a CEO and effectively run a large corporation. In this situation, the CEO is assuming the role of CEO for the large quick service restaurant chain. Often the question comes up on whether CEO candidates should be selected from the current executives in the firm or from outside the firm. Also some firms are quite large while others are just starting up.

a. Is it smarter for a board of directors hire a CEO from internal executives or external candidates from other companies? Obviously this candidate should be an experienced executive; but is it better to know the company or better to know the CEO role?

b. Assume the company is a relatively new an rapidly growing company. Does it matter if the CEO is the first one for this growing company? Is anything different?