D) Survey 100 randomly selected students from the school
Step-by-step explanation:
This gives an equal chance to everybody, so it's not biased and it is of everybody that goes to his school. A is only the people on the football team so its not students in his school. Walking to school has nothing to do with the survey topic and so thats also definitely not it. C again doesn't give a fair chance to everybody, so it would be possible to get an accurate, unbiased answer. D is definitely your answer!
