The table X below contains information on the population of four districts of country Z in the year 2016.
Use the information to answer the question which follows.

District	Population (million)	Land Area (km\(^{2}\))
A	5.5	60,000
B	8.0	105,000
C	6.7	125,000
D	4.8	88,000

(a) calculate the; 
i. total population of country Z
ii. total land area of country Z
iii. population density of country Z

(b) State four factors that are responsible for high population densities of countries.

(c) Explain three advantages associated with countries of high population density