The correct answer is (c).
The population density of a country or region is the number of people living per square kilometer. It is calculated by dividing the total population by the total land area.
According to the 2011 census, the population density of India is 382 people per square kilometer. The population density of the four states mentioned in the question is as follows:
- Assam: 376 people per square kilometer
- Karnataka: 319 people per square kilometer
- Madhya Pradesh: 231 people per square kilometer
- Chhattisgarh: 216 people per square kilometer
Therefore, the correct sequence of the states on the basis of descending order of their population density is (c): Madhya Pradesh, Chhattisgarh, Assam, Karnataka.
Option (a) is incorrect because it places Assam before Karnataka in the sequence. Option (b) is incorrect because it places Chhattisgarh before Madhya Pradesh in the sequence. Option (d) is incorrect because it places Karnataka before Chhattisgarh in the sequence.