The magma that creates new sea floor comes from the

a) asthenosphere

b) lithosphere

c) core

d) mantle

Option (D)

Explanation:

The new sea floor are formed along the mid-oceanic ridge, in a divergent plate tectonic setting where two plates move in the opposite direction. The convection current that forms in the mantle forces the magma of basaltic composition to rise up and results in the formation of cracks through which the magma erupt at the seafloor. These magma are deposited along this mid-oceanic ridge where the new materials are added and the rocks formed in and around this ridge are the youngest rocks.

Thus, the source of this magma is the mantle.

Hence, the correct answer is option (D).