Answer: C.)according to Earth’s existing magnetic field
Explanation:
Earth acts as a huge bar magnet. It has strong magnetic field due to presence of molten iron and nickle present in its outer core. A magnetic object acquires magnetic properties when placed in a magnetic field for a while.
Basalt is a volcanic rock. It is formed due to rapid cooling of lava on the surface of Earth. It contains iron oxides, iron-titanium oxides. Because of these oxides, Basalt can acquire strong magnetic properties. The domains align in the same direction as the Earth's magnetic field.
Thus, when new basalt forms along mid-ocean ridges, it becomes magnetized <u>C.) according to Earth’s existing magnetic field
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