Final answer:
Dashes are used to emphasize content, while parentheses are used to downplay content.
Step-by-step explanation:
Dashes are used to emphasize content, whereas parentheses are used to downplay content. Dashes place more emphasis on the enclosed content than either parentheses or commas. On the other hand, parentheses place less emphasis on the enclosed content than commas. So, the correct statement is a) True.