In: Economics
Answer.
(a). Firstly, the 4 definitions of economics are as follows,
Wealth definition of Economics, Proposed by Adam Smith
The two distinct object proposed by political economy which is
considered as a branch science are: (1)to provide plentiful revenue
or subsistence to the people or which aims mainly to provide
subsistence for themselves.
(2):In order to supply a revenue which is sufficient for the public
service to the state or common wealth.
Alfred Marshall’s Definition of Economics
Economics can be defined as two parts:(1) it is a science of
wealth
(2) it's a part of the social science of man's action in society
which deals with his deals to satisfy his wants in so far as the
efforts to satisfy his wants are capable of being measured in terms
of wealth, that is money.
Robbins’ Definition of Economics
Lionel Robbin defined economics as the subject that studies the allocation of scarce resources with countless possible uses.
According to Robbins "economics is the science which studies human behaviour as a relationship between ends and scarce means which have alternative uses".He said the following in his 1932 text "An Essay On the Nature and Significance of Economic Science"
Modern Definition of Economics
Economics is the study to employ scarce productive resources which could have alternative uses,with or without use of money ,the way people and society chose.It also aims to produce various commodities over time and distribute among various persons and groups of society now and in the future
(b) According to me, the best defenition of economics is considered to be the Modern defenition of Economics.
Only because it comments on low levels of inequality and unemployment and also on good replacing profit. It also comments on the economy disadvantages include lack of competition and lack of efficiency.
Hope I have answered your question correctly. Keep studying. Have a nice day.