Final answer:
The correct answer is A. Pyroclastic texture, which is associated with igneous rocks formed by explosive volcanic eruptions that rapidly cool the ejected ash and fragments, preventing large crystal formation.
Step-by-step explanation:
The texture that occurs when an igneous rock is formed mostly by ash, small broken crystals, fragments of rocks, and glass is known as pyroclastic texture. This type of texture is characteristic of rocks that have been formed through explosive volcanic activity, which rapidly cools the ejected material and does not allow time for large crystals to form.
Several other textures exist for igneous rocks, such as aphanitic (fine-grained), phaneritic (coarse-grained), and glassy, each related to the rate of cooling and the environment in which the rock forms. For example, a glassy texture in rocks like obsidian occurs when lava cools so rapidly that no crystals can form. Aphanitic textures are typical of extrusive rocks like basalt or rhyolite, where the rapid cooling at the surface results in small crystals.
Hence, Option A is correct.