Answer:
B. Yes, this is a valid inference because she took a random sample of the neighborhood
Step-by-step explanation:
A. Yes, this is a valid inference because the 30 families speak for the whole neighborhood - This is not correct because the families she asked do not speak for the whole neighborhood
C. No, this is not a valid inference because she did not take a random sample of the neighborhood - She did take random samples so this is not the answer "She puts all 120 of the neighborhood addresses in a hat and draws a random sample of 30 addresses."
D. No, this is not a valid inference because she asked only 30 families - I don't believe she needs to asked the whole neighborhood or more people because she did a random pull
So, the correct answer is B.