Which process of sedimentary rock formation occurs last?

cementation
compaction
deposition
erosion

The correct answer is cementation.

Explanation:

Cementation is the last step in the sedimentary rock formation process. In fact, the correct order is: weathering of rocks, transport of the weathering products, deposition of the material, compaction and cementation.

Sedimentary rocks are formed from fragments of other rocks. During weathering, the rocks on the Earth's surface disintegrate and fracture, leading to erosion.

These fragments will then be transported by water, wind, or ice, and as they do so they become even more fragmented.

The largest remaining parts of this transport are deposited near its source in the form of one layer on top of another horizontally.

Finally, this material compacts and expels the water it carries in the pores.

The minerals crystallize the water and form crusts, cementing the sediments and forming new rocks.

answer and explanation;

volcanic rocks are igneous rocks which form from lava, molten rock which has been thrust out of a volcano onto the surface of a rocky body such as an asteroid, planet, or dwarf planet.  

plutonic rocks are igneous rocks which form from subterranean chambers of molten rock or magma. plutonic rocks make up the base of continental crust as well as oceanic crust. their slow rate of formation causes them to be coarse grained since there is plenty of time for large crystals to form before the magma solidifies into rock.

the textural difference is that plutonic rocks are more coarse grained than volcanic rocks. plutonic rocks are coarse grained while volcanic are fine grained ; glassey or fragmental. since fine and coarse are adjectives the decision as to whether a rock is fine or coarse grained is generally made on the bases of whether or not the individual crystals can be seen in most if the rock.