NEOShield is an international consortium that focuses on addressing the threat of asteroids to Earth. Option 1 correctly identifies NEOShield as an international collaboration specifically designed to tackle the asteroid threat.

Option 2, regarding a geo-engineering project of OECD countries to combat global warming, is not related to NEOShield. Therefore, it is incorrect.

Similarly, option 3, which mentions NASA`s project to mitigate the effects of solar flares on communication systems, is unrelated to NEOShield. Hence, it is also incorrect.

Finally, option 4 suggests that NEOShield is a ballistic missile defense system developed by a group of countries. This option is not accurate, as NEOShield is focused on the asteroid threat and not on missile defense. Therefore, option 4 is incorrect.

In summary, option 1 is the correct answer as it accurately describes NEOShield as an international consortium addressing the threat of asteroids to Earth.