The correct option is C Both 1 and 2
India is the 4th country in the world to have its own regional SBAS after U.S.A, JAPAN and EUROPE. The GPS Aided GEO Augmented Navigation (GAGAN) is an implementation of a regional satellite-based augmentation system (SBAS) by the Indian government. The AAI’s efforts towards implementation of operational SBAS can be viewed as the first step towards introduction of modern communication, navigation, surveillance/Air Traffic Management system over Indian airspace. Further, GAGAN is the first system in the world that would be certified to serve the equatorial anomaly region with its unique IONO algorithm (IGM-MLDF: ISRO GIVE Model – Multi-Layer Data Fusion) designed and developed by ISAC in collaboration with vendor.