The Empirical Evidence on the Effectiveness of Non-Executive/ Outside Directors

The empirical evidence on the effectiveness of non-executive/ outside directors is conclusive and suggests that the latter increase firm value and performance.

A) No, the existing evidence suggests that non-executives reduce firm performance and value.
B) The existing evidence suggests that non-executives increase firm value, but only if they dominate the board of directors.
C) No, the existing empirical evidence is as yet inconclusive.
D) None of the above.