I believe the answer is c. appositive phrase
Answer:
The third one.
Explanation:
Most secondary characters serve as emotional support for the main.
In an essay it should only be one I'm pretty sure, but in a narrative as many as it takes to explain a lesson learned. If you were writing a book your conclusion would be whatever comes to you and whatever you feel the characters would do/say/feel.
Cob has been used since the 17th century as a building material. It is made by mixing dry sand, sifted clay and water. A cob house is a house that is made from this material. A benefit of using this material, is that it is sustainable and only uses natural products.