Answer:
The correct answer is option A.
Step-by-step explanation:
Monopoly refers to the market situation where there are large number of buyers but a single seller. There is no close substitute of the product. There is a restriction on the entry of new firms and exit of existing firms in the market.
All these are applicable to municipal water company to a high degree.
There are a number of grocery stores in the market and there is no restriction on their entry and exit.
Similar is the case with an online book store.
So, the correct answer is a municipal water company.