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.
Answer:
third
Explanation:
Summaries should be written in the third-person with an objective point of view.
Option 4, 'a quote from a customer describing how much their electric bill was lowered,' best supports evidence that solar panels save money. You are using a first hand source to prove to the audience that solar panels save money.