The correct answer is option 'D': Right to Constitutional remedies.

Explanation:
Dr. B. R. Ambedkar, the chief architect of the Indian Constitution, described the Right to Constitutional remedies as the heart and soul of the Constitution. This right is enshrined in Article 32 of the Indian Constitution and is considered to be the most fundamental and important right provided to the citizens.

Here is a detailed explanation of why Dr. Ambedkar referred to the Right to Constitutional remedies as the heart and soul of the Constitution:

1. Importance of Fundamental Rights:
- The Constitution of India guarantees several fundamental rights to its citizens, such as the right to equality, freedom of speech, right to life and personal liberty, etc.
- These rights enable individuals to lead a dignified life and protect them from any arbitrary actions by the state or fellow citizens.

2. Enforcing Fundamental Rights:
- The Right to Constitutional remedies provides a mechanism for individuals to enforce their fundamental rights.
- It allows any citizen to move to the Supreme Court or High Courts directly if their fundamental rights are violated or threatened.
- This empowers citizens to seek justice and hold the government accountable for any violations.

3. Remedies Available:
- Article 32 guarantees various remedies to protect fundamental rights, such as writs like Habeas Corpus, Mandamus, Prohibition, Certiorari, and Quo Warranto.
- These writs ensure that the government or any other authority does not exceed its jurisdiction or act unlawfully.
- They provide a means to correct any errors, omissions, or violations that may occur in the administration of justice.

4. Significance for a Democratic Society:
- The Right to Constitutional remedies is essential for the proper functioning of a democratic society.
- It acts as a safeguard against any potential abuse of power by the government or its agencies.
- It ensures that the citizens have access to justice and can seek redressal for any violation of their rights.

In conclusion, the Right to Constitutional remedies is considered the heart and soul of the Constitution because it enables citizens to enforce their fundamental rights and ensures that the government remains accountable. It acts as a cornerstone for the protection of individual liberties and the proper functioning of a democratic society.