The problem with the EVM is the use of cost as a proxy to manage time or schedule. When using Earned Value to measure schedule progress: a. The EV is very accurate measure of schedule progress. b. Schedule progress is not as important as cost, so it does not need to be very accurate. c. EV could overstate the progress if a cost intensive work package is delivered, but some low cost critical activities are delayed. d. None of the above is correct