The Empirical Evidence on the Relationship Between the Expected Return

The empirical evidence on the relationship between the expected return on stocks and their dividend yields show:

A) conclusive evidence that dividends should be set as low as possible.
B) conclusive evidence that dividends should be set as high as possible.
C) conclusive evidence that dividends don't matter.
D) inconclusive evidence; some show evidence that high dividend payouts are best, others show the opposite.
E) inconclusive evidence, although all studies show that high dividend payouts are best.