Option 1 -> SARAL is not in geostationary orbit; it operates in a sun-synchronous orbit at about 800 km altitude.
Option 2 -> SARAL is not designed for navigation purposes like GPS or IRNSS satellites.
Option 3 -> While it provides some meteorological data, weather monitoring is not its primary function.
Option 4 -> SARAL carries the AltiKa altimeter to measure sea surface height, wave patterns, and ocean parameters for oceanographic studies.
Hence, Option 4: Earth Observation Satellite to study oceanography -> SARAL (Satellite with ARgos and ALtika) is a joint Indo-French mission launched in 2013, specifically designed to study ocean surface topography, sea level variations, and marine meteorology -> correct