When each firm produces 8 units, Big Inc has a lower total cost, and when each firm produces 12 units, Mega crop has a lower total cost.
Explanation:
When each product is made 8 units, Big Inc does have a smaller total cost, and when each company produces 12 units, Mega Crop does have a smaller total cost.
A single company producing goods without near competition has a monopoly, whereas an oligopoly market does have an amount limited of extremely large companies producing similar or slightly separate goods. For both cases, the entrance of other businesses is significantly impeded.
By nationalization of a good or service like postal system a government could create a monopoly.