Final answer:
Jointing is most regularly patterned in coarse-grained rocks, specifically intrusive igneous rocks like granite and diorite, because they have large, interlocking crystals that can maintain clear, patterned fractures known as joints.
Step-by-step explanation:
The question asks about jointing, which is most regularly patterned in certain types of rocks. Jointing refers to the natural cracks or fractures that occur in rocks without the displacement of the sides relative to one another. This typically happens during the contraction as rocks cool or when rocks are unearthed by erosion, which reduces the pressure on them.
Based on the information provided, we can infer that fine-grained rocks, such as those that form from the quick cooling of lava on the surface of the earth, known as extrusive igneous rocks, are less likely to have pronounced jointing. Similarly, soil lacks the solidity to support jointing. Faulted rocks have undergone significant movement, which differs from the process of jointing. On the other hand, exfoliated rocks may display a type of jointing due to the release of pressure, but this is not patterned jointing; rather it results in sheet-like structures or foliation.
Therefore, coarse-grained rocks, including many intrusive igneous rocks that cool slowly and solidify beneath the earth's surface, are more likely to exhibit patterned jointing. Intrusive igneous rocks have large, interlocking crystals and are typically hard enough to maintain the clear, patterned fractures known as joints. Examples of coarse-grained igneous rocks include granite and diorite.
In summary, the answer to the student's question about where jointing is most regularly patterned is C) coarse-grained rocks.