Question

in the process of seafloor spreading, where is new seafloor created?
a mantle
b mid - ocean ridge
c trench

Explanation:

Seafloor spreading is a process in plate tectonics. New seafloor is created at mid - ocean ridges. Magma from the mantle rises at mid - ocean ridges, cools, and solidifies to form new oceanic crust (seafloor). The mantle is the source of the magma, not where the seafloor is created. Trenches are areas where oceanic crust is subducted (destroyed), not created.

Answer:

b. mid - ocean ridge