C because it sounds more formal and like you know what you are talking about !
cause-and-effect reasoning is mostly persuasive as it helps answer the question on <em>'how' </em> <em>one person, thing, or event causing another thing or event to occur </em> or <em>'why' something happens </em>making a statement objective and rational rather than a blind assertion/affirmation.
Hope this answer helps you, have a great day!