The information about the total cost for a firm is given below :

From this information find out : (a) Average fixed cost of producing 3 units, (b) Marginal cost of producing `4^(th)` unit, (c ) Output level when marginal cost is greatest , (d) Total variable cost of producing 5 units,
(e) Average variable cost of producing 3 units, (f) Averge total of producing 4 units.