D. Cause/Effect
When looking to explain the reasons why something happened, you’ll be looking into the “causes” of the “effect.” The link between two or more things where an element or elements are the outcome of the occurrence of something else that came before it. Here is the concept simplified.
Cause = why something happened (this can be singular or plural—“cause” or “causes”)
Effect = the thing that happened
It’s important to note that even though a cause will happen first, it doesn’t necessarily need to appear first in a sentence, paragraph, or paper. For instance, “I was tired because I stayed up too late.” Here, we see the effect of being tired coming first followed by the cause of staying up late, which is why I was tired.