Final answer:
Lavas and magmas are formed by different geological processes such as decompression melting, flux melting due to volatiles, and the addition of heat. Tectonic setting significantly influences magma composition, with subduction zones producing different magmas than mid-ocean ridges.
Step-by-step explanation:
The different types of lavas/magmas are formed by various geological processes related to the Earth's tectonic activities. These processes include decompression melting, flux melting (volatiles), and the addition of heat (conduction). In the context of tectonic settings, subduction zones often produce magmas distinct from those found at mid-ocean ridges because of the different conditions under which the mantle material melts. At mid-ocean ridges, decompression melting occurs due to diverging tectonic plates, leading to the formation of mafic magmas that result in basaltic lavas.
In contrast, subduction zones experience flux melting due to the hydration of minerals in the oceanic crust, which produces a range of magma compositions, often leading to more explosive volcanism and a variety of igneous rock types. So, the correct option in relation to the influence of tectonic setting on magma composition is that (c) Subduction zones produce different magmas than mid-ocean ridges.