The correct answer is "oceanic crust." At a divergent plate boundary, two tectonic plates are moving away from each other. As the plates separate, magma rises from the mantle to fill the gap. When this magma reaches the surface, it cools and solidifies, forming new oceanic crust. Therefore, the formation at a divergent plate boundary is oceanic crust.
At a divergent plate boundary, oceanic crust is formed.
