The correct answer is option 'C', the President or Prime Minister declares the opening of the Olympic games in the stadium. Let's explain this in detail.

The Opening Ceremony of the Olympic Games is a grand spectacle that marks the beginning of the event. It is a globally significant event that is watched by millions of people around the world. The ceremony is typically held in a stadium, and it is during this ceremony that the official declaration of the opening of the Olympic Games takes place.

Here is an explanation of why option 'C' is the correct answer:

Role of the President or Prime Minister:
- The President or Prime Minister of the host country is usually given the honor of declaring the opening of the Olympic Games.
- This role is significant as it represents the host country's recognition and acceptance of the responsibility of hosting the Games.
- The President or Prime Minister declares the opening by making a formal announcement in front of the audience present in the stadium and the millions watching the event on television.

Importance of the Role:
- The declaration of the opening of the Olympic Games by the President or Prime Minister holds great symbolic value.
- It signifies the unity and harmony among nations as athletes from various countries come together to compete in the spirit of fair play and sportsmanship.
- It also acknowledges the efforts put forth by the host country in organizing the Games and showcases their pride in hosting such a prestigious event.

Other Options:
- Option 'A' states that the President of the IOC (International Olympic Committee) declares the opening, which is incorrect. The President of the IOC plays a significant role in the organization of the Games but does not declare the opening.
- Option 'B' states that a member of the IOC declares the opening, which is also incorrect. While members of the IOC are involved in various aspects of the Games, they do not have the authority to declare the opening.
- Option 'D' states that the Chief Minister of any host state declares the opening, which is not accurate. The Chief Minister is a regional political position within a country and does not have the authority to declare the opening of the Olympic Games.

In conclusion, the correct answer is option 'C', the President or Prime Minister, as they have the honor and responsibility of declaring the opening of the Olympic Games during the Opening Ceremony.