You are considering four hotels that differ from each other with respect to their price and customer reviews:

H4

Explanation:

Looking at the reviews given per price, a conclusion can be made that the higher the price of staying in the hotel, the higher the ratings given which would imply that the hotels charging higher, have better amenities.

This does not hold for H4 however as they are charging more than H1 but still getting the same reviews as them.

This could either mean that H1 is efficient enough to be getting the same rating for the same price as H4 or that H4 is inefficient such that they are not utilizing their amenities enough to get a higher rating than H1 who they should be better than.

Either scenario point to inefficiency on H4's part.

answer: a. the kind of population living in your neighbourhood.

the census explorer data tool by the us census bureau allows the user to zoom in on any neighbourhood within the united states and find the kind of people residing in that by race and age.  

the tool needs to needs to be used twice – once in order to find what type of people reside in a neighbourhood, and then to see the age groups of the people in the same neighbourhood.