Answer:
Option C) The firm's cost of equity is unaffected by a change in the firm's tax rate.
Step-by-step explanation:
To calculate the firm's Cost of Equity we can use the CAPM Model which indicates the following:
ER: Rf + Bi (Erm + Rf)
ER: (Expected Return)
Rf: (Risk Free)
Bi: (Beta)
Erm: (Expected Return on Market)
In this way we can calculate the cost of equity only considering the Risk Free Rate and the Market Risk Premium (Erm + Rf), in this case we don't need the tax rate to calculate our cost of equity which yes it's neccesary in the use of WACC Model.