Which of the following statements are true?

1. As a result of the tension that exists between the shareholders and the bondholders of a firm, agency costs play a role in the search for the firms optimal capital structure.
2. Firms with intangible assets should, on average, have lower debt-to-value ratios.
3. According to the trade-off theory of capital structure, firms that have a low marginal tax rate should be highly levered (i.e., finance their operations with debt mainly).