The `Beijing Declaration` is a document that addresses a specific issue. To determine the correct answer, let`s dissect each option:

Option 1: Rights of children - This option refers to the rights and welfare of children. Although the `Beijing Declaration` may mention children`s rights indirectly, it is not the main focus of the declaration.

Option 2: Rights of women - This option refers to the rights and empowerment of women. The correct answer is option 2 because the `Beijing Declaration` primarily focuses on addressing gender inequality, promoting women`s rights, and advocating for gender equality.

Option 3: Right to development - This option relates to the concept of the right to development, which focuses on economic, social, and cultural development for all individuals. While the `Beijing Declaration` may touch upon development issues, it is not the central concern of the declaration.

Option 4: Reduction of tariffs - This option refers to the decrease in import/export duties on traded goods. The `Beijing Declaration` does not primarily deal with economic policies such as tariff reduction.

In conclusion, the correct answer is option 2 - the `Beijing Declaration` is concerned with the rights of women and gender equality.