The Demand for the Output of a Multi-Firm Industry Is

The demand for the output of a multi-firm industry is Q_T = 50 !2.5P. The total cost of production of an individual profit-maximizing firm in this industry is TC₁= 4Q₁. If this industry is comprised of 19 firms, the Cournot-Nash equilibrium output for firm 1 is:

A) 0.2 units.
B) 0.4 units.
C) 0.6 units.
D) 0.8 units.
E) 1 unit.