The Tshwane Declaration, also known as the Tshwane Principles on National Security and the Right to Information, was signed in October 2006. It is a document that focuses on the importance of access to information and the role of national security in promoting transparency and accountability.

Among the given options, the country or countries that signed the Tshwane Declaration in October 2006 are India and South Africa (Option 2). This can be confirmed by examining the historical context and the participation of these countries in the event.

1. China and South Africa (Option 1): While both China and South Africa are significant countries, there is no concrete evidence to suggest that China was one of the signatories of the Tshwane Declaration. China has its own approach to information access and national security, and its involvement in the Tshwane Declaration has not been documented.

2. India and South Africa (Option 2): India`s participation in the Tshwane Declaration is well-documented. In October 2006, India`s Minister of State for External Affairs, Anand Sharma, attended the 2nd International Conference of Information Commissioners held in Tshwane, South Africa. The conference focused on the importance of access to information, and India`s presence demonstrates its commitment to the principles outlined in the Tshwane Declaration.

3. South Africa and Botswana (Option 3): While Botswana is an important African nation, there is no evidence to suggest that it was involved in signing the Tshwane Declaration. The Declaration primarily focused on the host country, South Africa, and other international participants.

4. Saudi Arabia and South Africa (Option 4): Saudi Arabia`s involvement in the Tshwane Declaration is not documented. Saudi Arabia has its own policies regarding information access and national security, and there is no public record of its participation in the Tshwane Declaration.

In conclusion, based on historical evidence and the documented participation of various countries, the Tshwane Declaration in October 2006 was signed by India and South Africa (Option 2).