Answer:
the number of skyscrapers in 5 different cities
Step-by-step explanation:
A bar graph is a perfect way to show the relation between two components where the components are not variable. Here if you look at second option, the two components are: No. of skyscraper and cities. It is evident that the skyscraper's no. is not a variable and will remain fixed.
While if you look at the other option, the components are variable and thus can not be represented on a bar graph.