In 1994, India proved its expertise in space technology by demonstrating its ability to launch geostationary satellites, hence the correct answer is option 4.

Option 1 is incorrect as in 1994, India had not demonstrated its capability to design advanced intercontinental ballistic missile warning systems.

Option 2, although India has had the capability to build satellites, this is not specifically what was demonstrated in 1994.

Option 3 is also incorrect as the development and exhibition of stealth missiles are generally associated with defense technology, not space technology.

Therefore, by examining what India specifically achieved in space technology in 1994, we can confirm that the correct answer is indeed option 4, the ability to launch geo-stationary satellites.