Answer:
B. Convenient is your best answer
Step-by-step explanation:
The Polling Organization may think that the skate park is the best place to survey because there may be a large body of people (75+) that can give their opinions.
It is not A, because all opinions are biased.
It is not C, because the people themselves are not volunteering.
It can be D, but it is not all that random.
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