Detailed Explanation:

Answer: Option 3 — National Payments Corporation of India

The National Payments Corporation of India (NPCI) operates the National Financial Switch (NFS), which is the largest network of shared ATMs in India. NFS links ATMs across all banks, enabling customers to access any bank's ATM for cash withdrawal and other banking services, facilitating seamless inter-bank ATM transactions nationwide.

📝 Short Notes: National Payments Corporation of India (NPCI)

• Establishment: NPCI was incorporated in 2008 as an umbrella organization for operating retail payments and settlement systems in India.
• Ownership: It is an initiative of the Reserve Bank of India (RBI) and Indian Banks' Association (IBA) under the provisions of the Payment and Settlement Systems Act, 2007.
• National Financial Switch (NFS): Launched in 2004, NFS is the largest network of shared ATMs in India, connecting over 1 lakh ATMs across banks.
• Key Services: NPCI operates multiple payment systems including UPI (Unified Payments Interface), IMPS (Immediate Payment Service), RuPay card scheme, BHIM, AePS (Aadhaar Enabled Payment System), and NFS.
• UPI: Unified Payments Interface is NPCI's flagship real-time payment system that has revolutionized digital payments in India.
• RuPay: India's own domestic card payment network, competing with Visa and Mastercard, launched by NPCI in 2012.