If a major solar storm (solar flare) reaches the Earth, which of the following are the possible effects on the Earth? 1. GPS and navigation systems could fail. 2. Tsunamis could occur at equatorial regions. 3. Power grids could be damaged. 4. Intense auroras could occur over much of the Earth. 5. Forest fires could take place over much of the planet. 6. Orbits of the satellites could be disturbed. 7. Shortwave radio communication of the aircraft flying over polar regions could be interrupted. Select the correct answer using the code given below:

Answer: C. Statements 1, 3, 4, 6 and 7 are correct effects of a major solar storm; statements 2 and 5 are wrong. A major SOLAR FLARE / coronal mass ejection (CME) reaching Earth disrupts Earth's magnetosphere and ionosphere, causing geomagnetic storms. (1) GPS/navigation failure: CORRECT. Ionospheric disturbances degrade satellite-to-ground signal accuracy. (2) Tsunamis at equator: WRONG. Tsunamis are caused by sub-sea earthquakes, landslides or impacts — NOT by solar storms. (3) Power grid damage: CORRECT. Geomagnetically Induced Currents (GICs) can overload transformers; the 1989 Quebec blackout was caused by this. (4) Intense auroras: CORRECT. Auroras occur as charged particles excite atmospheric gases; major storms cause auroras visible at low latitudes. (5) Forest fires globally: WRONG. Solar storms don't cause planetary forest fires. (6) Satellite orbital disturbance: CORRECT. Increased atmospheric drag at altitudes 200-600 km can decay satellite orbits. (7) Shortwave radio disruption at polar regions: CORRECT. Polar Cap Absorption events absorb HF radio signals over Arctic/Antarctic regions, disrupting transpolar aviation communications. Source: NASA Space Weather / NOAA Space Weather Prediction Center.