Answer:
C. New ocean crust forms.
Explanation:
At divergent margins, it is true that new ocean crusts forms at the margins.
Along a divergent margin, two lithospheric plates are moving apart from one another.
Usually, when this occurs between two oceanic plates, the underlying mantle upwells to fill the void. The cooling and solidifying mantlic materials furnishes the formation of a new crust.
This is the oceanic crust.