Answer:
d. Writers either avoid using commas or overuse commas, so their sentences are unclear or difficult to read.
Explanation:
A comma can be defined as punctuation mark that is typically used for indicating a break elements of a series or list in a sentence. Also, it's used to indicate the shortest pause in a sentence.
A coordinating conjunction can be defined as a word that is used for joining two words, phrases or sentences having similar grammatical rank and are syntactically equal.
Generally, coordinating conjunction are considered to be the most popular and widely used form of conjunctions.
In English language, there are seven (7) coordinating conjunction and these includes; for, and, nor, but, or, yet, so.
As a general rule, a coordinating conjunction requires the use of a comma before the conjunction.
In this scenario, the coordinating conjunction used in the sentence is "so" and as such a comma is written before it.
Hence, the sentence that has a correct comma usage is; "Writers either avoid using commas or overuse commas, <u>so</u> their sentences are unclear or difficult to read."
