Final answer:
Sedimentary rocks are classified by composition and texture, depending on the processes they result from, such as clastic deposition or chemical and organic formation.
Step-by-step explanation:
Sedimentary rocks are classified primarily by composition and texture. These classifications are based on how the rocks are formed, from either clastic material or chemical and organic processes.
Clastic sedimentary rocks are formed by particles that are weathered, eroded, and then transported to an area where they are deposited, typically categorized by grain size.
The texture of clastic sedimentary rocks can also be identified by the roundness of grains and how well they are sorted.
In contrast, chemical sedimentary rocks are formed from minerals that precipitate from solution, as seen with salts, while organic sedimentary rocks are formed from the accumulation of organic debris such as in the formation of coal, oil, and natural gas.
Therefore, the correct classification of sedimentary rocks for your question is by composition and texture.