The demand equation for a monopolist's product is p = 200 - 0.98q, where p is the price per unit (in dollars) of producing q units. If the total cost c (in dollars) of producing q units is given by c = 0.02q^2 + 2q + 8000, find the level of production at which profit is maximized.
a) 99 units
b) 81 units
c) 90 units
d) 89 units
e) 101 units