If parties in each market focus on fulfilling their own self-interest, then there is no need to study economy as a whole. But economists found that they had to look further. Which of the following can be the reason?

All of above

the correct answer is Option 4" All of above

Macroeconomics tries to address situations facing the economy as a whole. Adam Smith, the founding father of modern economics, had suggested that if the buyers and sellers in each market take their decisions following only their own self-interest, economists will not need to think of the wealth and welfare of the country as a whole separately. But economists gradually discovered that they had to look further.

In some cases, the markets did not or could not exist. Secondly, in some other cases, the markets existed but failed to produce equilibrium of demand and supply. Thirdly, in a large number of situations, the State or the people as a whole had decided to pursue certain important social goals unselfishly like employment, administration, defence, education and health for which some of the aggregate effects of the microeconomic decisions made by the individual economic agents needed to be modified.