Answer:
Public bus must be used for city-B
Explanation:
City-A:
total population =51,242
area =89.22 mi^2
we can find population density
population density=( total population)/(total area)


Population density =574.3331
City-B:
total population =50178
area =8.12 mi^2
we can find population density
population density=( total population)/(total area)


Population density =6179.55665
Since, the population density of city-B is greater
so, public bus must be used for city-B