Which of the following is the space-weather term for an extreme geomagnetic storm?
B9
X5
M9
G5✓الإجابة الصحيحة
الشرح
NOAA rates geomagnetic storms on a G scale running from G1, minor, to G5, extreme, so G5 is the extreme case. B9, M9, and X5 are solar flare designations on the X-ray flux scale and describe flares rather than geomagnetic storms.