4. Short sale calculations. a) A client wishes to sell short 500 shares of listed FED Company Ltd. (eligible for reduced margin) at its current market price of $15. How much must the client put up as margin? b) Assume that later on the price of FED's shares declines to $12. Will the client have to put up more margin? How much must be added to, or withdrawn from, the account? c) if the price of FED's shares advanced to $18 instead of declining, would the client receive a margin call? If so, for how much