Answer:
The correct answer is option D. at ocean ridges.
Step-by-step explanation:
New oceanic crust is continuously forming while magma appears at mid-ocean ridges.
Age and the rate of spread determine the characteristics of an oceanic crust.
The study of the crust is easy to carry out because it is now exposed on land, since it has been formed millions of years ago. Although still a large amount of oceanic crust remains underwater. Therefore, any type of new crust is initially generated at ocean ridges.