Which of the following is correct?

A WACC as used in capital budgeting is an estimate of a company's before tax cost of capital

The percentage flotation cost associated with issuing new common equity is typically smaller that the flotation cost for new debt

The WACC as used in capital budgeting is an estimate of the cost of all the capital a company has raised o acquire its assets

There is an "opportunity cost" associated with using retained earnings, hence they are not free

The WACC as used in capital budgeting would be simply the after tax cost of debt if the firm plans to use only debt to finance its capital budget in the coming year