Answer: A) All of the families in his neighborhood
<u>Step-by-step explanation:</u>
A) Polling every household in the neighborhood will provide an accurate statistic of those that use the pool, those that do not use the pool, and their finances.
B) This limits the survey to only those who are using the pool on Saturday.
C) This limits the the survey to only those who do not use the pool.
D) 10 families from each of the 20 neighborhoods would be a random selection but there isn't enough information provided to determine if this covers the entire neighborhood or only a portion of the neighborhoods (since it states the 20 closest to him) or if 10 families is a sufficient percentage of the neighborhood population.