Read the passage and answer the question.
In national no less than in individual life there are no watertight compartments. No sharp lines can be drawn to mark off the political from the moral, the social from the economic regions of life. Politicians often talk as though one has only to introduce certain political and economic changes for paradise to descend on earth, forgetful of the fact that the efficiency of an institution depends on the way it is worked, which itself is determined by the character and wisdom of the men who work it.
Which one of the following phrases best helps to bring out the precise contextual meaning of "watertight compartments" ?

Options

A. Activities of life unaffected by public opinion.
B. Spheres of life where no liberty of opinion is tolerated.
C. Ways of life peculiar to each nation and each section of society.
D. Spheres of life which are independent and unconnected with one another.