Correct Answer: Three

Solution : The correct option is Three.

The three categories used by the Industrial Policy Resolution are:

1. Schedule A Industries: These are exclusively available for use by the public sector and the government enjoys a monopoly in some areas.

2. Schedule B Industries: The public and private sectors are welcome to participate in these industries. There is no public sector monopoly in these.

3. Schedule C Industries: All of these fall under the purview of the private sector. The government has little effect on how they operate or are regulated.