Answer:
D. It formed from magma that cooled quickly
Explanation:
From several experiments, geologists have come to terms with the fact that when magma cools rapidly, it does not give room for large and big sized crystals to form. Instead, tiny, little crystals would be formed.
For example, obsidian and most volcanic rocks.
When a magma has enough time to cool and solidify, we see very big crystals of minerals in them.
