Respuesta :
After reading these two paragraphs of excerpt from Ambrose Bierce's "An Occurrence at Owl Creek Bridge" I would say that there should have been some options to identify the phrase which highlights the use of everyday characters in realism. If you had attached some variants it would have been much easier for me to give you the answer that will fit your task, but I can give you somenting that will really help you - No service was too humble for him to perform.
No service was too humble for him to perform
This line shows that the character is an everyday person. A person of a high social class would not be willing to complete any service. However, a person of a lower social class, who is also described as humble, would be more likely to perform any service asked of him. Of the possible options, this is the best choice.