The most populated state in India as per the Census 2011 is Meghalaya. Let's understand why Meghalaya is the correct answer.

Population in Census 2011:
- Goa: According to the Census 2011, Goa has a population of approximately 1.46 million.
- Mizoram: Mizoram has a population of around 1.09 million as per the Census 2011.
- Meghalaya: Meghalaya has a population of about 2.97 million as per the Census 2011.
- Sikkim: Sikkim has a population of around 0.61 million as per the Census 2011.

Meghalaya's Population:
Meghalaya is a state located in northeastern India. It is known for its natural beauty, lush green landscapes, and unique culture. The state has a diverse population consisting of various ethnic groups.

Reasons for Meghalaya's High Population:
1. Tribal Population: Meghalaya is predominantly inhabited by tribal communities. The major tribes in Meghalaya include the Khasi, Jaintia, and Garo tribes. These tribes have a significant population, contributing to the overall population of the state.

2. High Birth Rate: Meghalaya has a relatively high birth rate compared to other states in India. This contributes to the growth of the population over time.

3. Limited Outmigration: Meghalaya has a limited outmigration compared to other states. Many people from Meghalaya prefer to stay within the state rather than migrating to other parts of the country. This contributes to the population growth within the state.

4. Improved Healthcare: Over the years, Meghalaya has witnessed improvements in healthcare facilities, leading to a decline in mortality rates. This has resulted in a higher population growth rate.

Conclusion:
Based on the Census 2011 data, Meghalaya is the most populated state among the given options. Factors such as a significant tribal population, high birth rate, limited outmigration, and improved healthcare have contributed to the state's high population.