It is the kind of monopoly where only one seller operates in the market with having no close substitutes. Here there is absolutely no competition. This type of monopoly in real market is very rare.
Here also single seller operates through the market with no close substitutes. But, some remote substitutes can be found in the market. Here, seller will have very small competition.
Example: Airtel is facing competition from BSNL.
Here the monopolist charges different price to different consumers for the same product. It prevails in more than one market.