When should firms follow "the Big-U" in their calculation of a project-specific WACC?

1 When the new project differs from the average project of the firm in terms of risk

2 When the new project differs in its financing (debt and equity weights) from the firm's overall debt and equity [i.e. capital structure] weights

3 When the new project differs in its financing (debt and equity weights) from the pure plays' average debt and equity [i.e. capital structure] weights

4 All of the above