The correct answer is B. opposite.
A magnetic storm is a disturbance in the Earth’s magnetosphere caused by a solar wind shock wave and/or a coronal mass ejection. The magnetic field generated due to a magnetic storm is directed in the opposite direction to the Earth’s main field. This can cause problems for satellites and other spacecraft in orbit, as well as for power grids and telecommunications systems on Earth.
Option A is incorrect because the magnetic field generated due to a magnetic storm is not directed in the same direction as the Earth’s main field.
Option C is incorrect because the magnetic field generated due to a magnetic storm is not directed southward.
Option D is incorrect because the magnetic field generated due to a magnetic storm is not directed northward.