Answer :
D. At the center of the mid-ocean ridge. because it has to be above ground
Answer:
D. At the center of the mid-ocean ridge
Explanation:
(I hope I helped)
I took the test here is proof that this is correct:
![View image ACarter03](https://us-static.z-dn.net/files/d10/e041c339f609a01a11ead26f82c141d4.png)