The correct answer is option 'A' - Mizoram.

Mizoram has the highest percentage of Scheduled Tribe population to its total population among the given Indian states. Let's explore the reasons behind this.

- Mizoram's Demographics:
Mizoram is a state in northeastern India, known for its rich cultural heritage and natural beauty. The state has a population of approximately 1.1 million people, according to the 2011 census. Out of this population, a significant percentage belongs to the Scheduled Tribe category.

- Scheduled Tribe (ST) Population:
Scheduled Tribes are indigenous communities in India that are recognized by the government for their distinct culture, language, and socio-economic characteristics. These tribes are given certain privileges and reservations to uplift their socio-economic status. Mizoram is home to several Scheduled Tribes, including the Mizos, Lushais, Hmars, and Chakmas.

- Tribal Dominance in Mizoram:
Mizoram has a predominantly tribal population, with the Mizo tribe being the largest and most influential. The Mizo community has played a significant role in shaping the state's culture, politics, and development. They have their own language, traditions, and customary laws, which are deeply rooted in their tribal heritage.

- Reasons for High Percentage:
There are several reasons why Mizoram has the highest percentage of Scheduled Tribe population to its total population:

1. Historical Background: Mizoram has a long history of tribal settlements and migrations. The tribal communities have inhabited the region for centuries, maintaining their distinct identity and lifestyle.

2. Geographical Isolation: Mizoram is located in a remote and hilly region of northeastern India, bordering Myanmar and Bangladesh. The geographical isolation has contributed to the preservation of tribal culture and traditions.

3. Preservation of Tribal Identity: Mizoram has made significant efforts to preserve and promote tribal culture. The state government has implemented various policies and programs to protect the rights and interests of the Scheduled Tribes.

4. Inclusion of Tribal Communities: The tribal communities in Mizoram actively participate in the state's governance and decision-making processes. They have their own autonomous district councils, which have limited legislative and executive powers.

Overall, Mizoram's high percentage of Scheduled Tribe population is a result of its historical, geographical, and cultural factors. The state has successfully maintained its tribal identity and has made significant progress in ensuring the welfare and development of its indigenous communities.