Why is the national average alone not enough while planning for population growth?

Correct answer: Because regional differences may be hidden in the average

Direct answer: A is correct. A national average combines data from many regions into one figure. That figure may be useful as a broad summary, but it can hide important differences: one region may have very high growth, another may have low or negative growth, and a third may face unusual population density or service pressure. Planning needs local information about population size, growth rate, age structure, migration, resources and facilities. A is correct because it recognizes that averages can conceal regional variation. B is wrong because averages are calculated and widely used, although they are not sufficient alone. C is wrong because regions do not necessarily grow at the same rate. D is wrong because averages can describe population and many other subjects, not only weather. Memory cue: an average gives the centre, but planning also needs the spread and local differences.