I'll answer this question based on the definition of an objective summary (a summary having no signs of bias or opinion).
So the sentence that best describes the example of an objective summary is:
"<span>Using Colorado Springs as his focal point, Mr Schlosser takes the reader on a behind-the-scenes tour of the fast-food industry that includes slaughterhouses, poultry processors, artificial flavors."
When we say objective, this means that the summary is based on the details presented and not mixed with any emotional ideas. Based on the statements above, the one that presents a summary that is presented in an objective way is option B.