Answer:
ethos
Explanation:
The reason its ethos is because its asking for credibility
hope this helps :)
By explaining problems and giving solutions! this is the best fit because the other two might make sense at a first glance, but only explaining problems and solutions would be an effective way to teach people how to set up an aquarium by giving them examples of what to do and what not to do whereas the others are just him talking about his aquarium.
Answer:
"an" open house
Explanation:
They were missing the "an."
A. a research question would be the most fitting to your question.