Answer:
B. decisions made by individual households and firms.
Explanation:
Economics is the study of choice to satisfy unlimited wants from limited resources, having alternative uses.
'Micro' word gets origination from greek language, meaning 'small'
Micro Economics is the study of 'individual' economic participants - individual households' & individual firms' choice decisions
Eg : Price of a good, Utility maximising consumption of consumer, profit maximising output of a producer/ seller.