In joint sessions of the Parliament, the Lok Sabha Speaker addresses the members of both the Lok Sabha and the Rajya Sabha. The joint session of the Parliament is called to fulfill certain specific constitutional requirements, as mentioned in Article 108 of the Indian Constitution.

The joint session is presided over by the Lok Sabha Speaker. The Speaker is the presiding officer of the Lok Sabha and holds a significant position in the parliamentary system of India. The Speaker is elected by the members of the Lok Sabha and is responsible for maintaining order and decorum during the parliamentary proceedings.

Key Points:
- The joint session of the Parliament is called for specific purposes, such as the election of the President, the address by the President, and the passage of certain important bills.
- The President of India can address the joint session of the Parliament at the beginning of the first session after each general election and the first session of each year.
- However, in the case of the address by the President, it is the Speaker of the Lok Sabha who invites the President to address the joint session.
- The Prime Minister and the Chairman of Rajya Sabha do not address the joint sessions of the Parliament. The Prime Minister, as the head of the government, addresses the Parliament separately during the regular sessions to present the government's policies and initiatives.
- The Chairman of Rajya Sabha, as the presiding officer of the Rajya Sabha, does not have the authority to address the joint sessions of the Parliament.

Conclusion:
In conclusion, the correct answer to the question is option 'D' - The Lok Sabha Speaker. The Speaker of the Lok Sabha presides over the joint sessions of the Parliament and addresses the members of both the Lok Sabha and the Rajya Sabha. The joint sessions are called for specific constitutional purposes and the Speaker plays a crucial role in maintaining order and conducting the proceedings.