The correct answer is option 2: Defence cooperation and intelligence sharing.

In the formation of the Indo-Pacific Economic Framework for Prosperity, the member countries engaged in collective discussions towards future negotiations on four pillars. The first pillar is clean energy, decarbonisation, and infrastructure, which suggests a focus on promoting sustainable energy sources, reducing carbon emissions, and improving the development of infrastructure projects. The second pillar is supply chain, which implies efforts to enhance trade connectivity and strengthen supply chains among the member countries.

The third pillar, tax and anti-corruption, indicates the importance of addressing tax-related issues and combating corruption in the Indo-Pacific region. This suggests a commitment to promoting fair and transparent financial systems and business practices.

However, the second option, defence cooperation and intelligence sharing, is not mentioned as one of the pillars. This implies that while the member countries may engage in defense and security cooperation, it is not specifically included as a part of the economic framework for prosperity under discussion.