This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
This question seems familiar with the topic earth science so,

If it is about the convergence of two oceanic plates then a Mountain will be formed on top of Plate B. 

If it is about diverging continental plates and oceanic plates, then if plate B is the continental plate then a Mountain will also be formed on top of Plate B.
12 4 12