Where is a deep ocean trench being formed? A. In the Atlantic ocean where the plates are separating.
B. In the Pacific ocean where an oceanic plate is subducting beneath a
continental plate.

B. In the Pacific ocean where an oceanic plate is subducting beneath a

continental plate.

Explanation:

Deep ocean trenches are being formed in the Pacific ocean where an oceanic plate is subducting beneath a continental plate.

Ocean trenches are natural depression within the earth usually formed along the margins of convergence between two plates.