C. Use a colon. A colon signals a pause stronger than a semicolon and suggests a more direct relationship between two ideas. A colon tells the reader that what follows will illustrate or amplify what has gone before. By July 1990, he had turn in his resignation. Although writers have an option about the use of commas with short clauses and phrases, inadequate punctuation of some short introductory phrases can confuse readers because they misread the complete sentence and then have to reread to separate the elements.
Writers have to be careful and insert the comma when it is necessary for readability.
In San Antonio jazz and mariachi bands vie for prominence. When you revise your text for comma punctuation, one thing to do is to ask yourself whether your reader would be able to process your sentence. Try reading your text aloud and see where you take breaks and pause. In non-technical writing the comma is more of an option in this case than it is in legal writing. Writers can signal non-essential or explanatory information with a pair of commas.