Disability under a State plan.

You will also be considered disabled for payment of supplemental security income benefits if— (a) You were found to be permanently and totally disabled as defined under a State plan approved under title XIV or XVI of the Social Security Act, as in effect for October 1972; (b) You received aid under the State plan because of your disability for the month of December 1973 and for at least one month before July 1973; and (c) You continue to be disabled as defined under the State plan.