Option 1 -> Planning Commission was a policy-making body for economic planning, not specifically for coordinating rural financing institutions.
Option 2 -> State Bank of India is a commercial bank that provides banking services but is not the apex coordinating body for rural financing.
Option 3 -> Self-help groups are grassroots-level community organizations for micro-credit, not an apex coordinating body.
Option 4 -> National Bank for Agriculture and Rural Development (NABARD) was established in 1982 specifically as an apex institution to coordinate rural credit.
Hence, National Bank for Agriculture and Rural Development -> NABARD was set up by an Act of Parliament in 1982 to serve as the apex body for coordinating the activities of all institutions involved in rural financing, including cooperative banks, regional rural banks, and commercial banks. It provides refinance facilities and supervises cooperative credit institutions -> correct