Explanation:

The correct option is (d) 1, 2 and 3 only. NITI Aayog's Action Agenda for enhancing digital connectivity is a comprehensive strategy that encompasses all three listed pillars. Firstly, 'Developing software for services that can be provided digitally' (1) is crucial for delivering e-governance, e-health, and e-education. Secondly, 'Enhancing digital infrastructure' (2) involves building robust networks, broadband access, and data centers to support these services. Thirdly, 'Empowering citizens digitally' (3) focuses on digital literacy and inclusion, ensuring that citizens can effectively access and utilize digital services. All three components are interdependent and essential for a holistic approach to digital transformation.