Option 1 -> Long term planning relates to normative economics and policy formulation.
Option 2 -> Future policies and planning involve normative judgments about what ought to be done.
Option 3 -> What should be done is the domain of normative economics which deals with value judgments.
Option 4 -> How the different mechanisms function is what positive economics studies.
Hence, Option 4: How the different mechanisms function -> Positive economics is concerned with objective, fact-based analysis of economic phenomena. It describes and explains how the economy actually works, focusing on cause-and-effect relationships and the functioning of various economic mechanisms without making value judgments. It deals with 'what is' rather than 'what ought to be', making it descriptive and analytical in nature. -> correct