I would say it is probably common knowledge, because it isn't someone else's idea, but if you found it online or in an article you would probably want to credit any thoughts, ideas, or quotes. Be sure to state whose calculated this number also.
C. to distinguish between his own life and the culture of his Grandparents.
The key to the sentence is the word murder. Whoever was saying the sentence was trying to tell you that he or she had a sister who was murdered just 20 feet from the playing field.
Twenty feet really isn't very much. Most small cars are just 4 feet shorter than 20 feet. That's not much.
So whoever is saying this is saying that the wonders of playing soccer could not overcome the awful feeling he/she must have knowing that his sister died there. Every time the narrator got on the field, he would be reminded of her death.
The correct answer is A. Makes him feel superior
It can be a noun and adjective.
