Sound reasoning is essentially a valid argument/claim with evidence to back it up. The argument needs to be written based on true premises and logical fallacies shouldn't be present. A sound argument typically requires an explanation to back up a clear message. A mix of ethos, pathos, and logos are present in a sound argument.
Compound-word prepositions<span> are made up of two or more words that act as adverb or those words that describe an action in terms of the setting, time, manner or frequency. The answer is </span>C. The lightning struck from out of the blue in which the compound-word preposition is "<span>from out of the blue"</span>
