Explanation:

- Article 85: This Article deals with sessions of the Parliament, including prorogation and dissolution. It mandates that there should not be a gap of more than six months between two sessions.

- Article 89: This Article is about the role of the Chairman and Deputy Chairman of the Rajya Sabha. It is not related to the sessions of Parliament.

- Article 90: This Article pertains to the disqualification of the Deputy Chairman of the Rajya Sabha.

- Article 101: This Article addresses the vacation of seats, not sessions of Parliament.

Your answer is Article 85. .