If a Company Fails to Accurately Predict It's Cost of Equity

If a company fails to accurately predict it's cost of equity, then

A) the firm's WACC will also be inaccurate.
B) the firm may not be using the proper interest rate to estimate NPV.
C) the firm my incorrectly accept or reject projects based on decisions made using the cost of capital computed with an incorrect cost of equity.
D) all of the above are true.