At a convergent boundary, two plates
a. collide
b. separate
c. slide past each other
d. move apart

At a convergent boundary, two plates come together. The correct response is Option A.

Explanation:

A convergent boundary is when two geological plates come together. This causes the edges of one or even both plates to fold in on each other. This is was creates mountain ranges and the trenches that are evident on the seafloor. It is common for volcanoes to form along convergent plate boundaries. These regions are also prone to earthquakes. At convergent boundaries, oceanic crust is forced down under the continental plate and this creates granite as the magma rises to the surface. This is how the continents tend to move or grow vis-a-vis the ocean.

Countries trade with each other when, on their own, they do not have the resources, or capacity to satisfy their own needs and wants. By developing and exploiting their domestic scarce resources, countries can produce a surplus, and trade this for the resources they need. You can integrate all of this into your question. Hope this helped.