Which sentence uses dashes for emphasis correctly?

• A. The answer (if you think about it) was obvious.
• B. The answer — if you think about it — was obvious.
• C. The answer—if you think about it—was obvious.
• D. The answer (if you think about it) was obvious.

Answer: (C)

Using dashes to emphasize means inserting a nonessential phrase directly into the sentence to give it extra punch, like a quick interruption that catches the reader’s attention. Em dashes are best when they enclose the aside without spaces around them in standard American typography, so the sentence reads smoothly and the emphasis feels tight.

The emphasis here comes from the aside “if you think about it,” set off by em dashes without spaces. This makes the interruption feel natural and makes the main point—“The answer … was obvious”—stand out more than if you used parentheses or spaced dashes. Parentheses would soften the emphasis, and dashes with spaces around them look a bit odd in formal writing. So the unspaced dash version is the clearest, most direct way to emphasize the aside.