Which of the following areas of study typifies macroeconomics as opposed to microeconomics?

a. the effect on the economy of changes in the nation's unemployment rate

b. the effects of rent control on the availability of housing in New York City

c. the economic impact of tornadoes on cities and towns in Oklahoma

d. how tariffs on shoes affect the shoe industry

All of these areas are macroeconomic because all of them involve some part of the economy as a whole. In all of these cases, the gvoernment is involved - either as a keeper of data (such as unemployment statistics), or as a regulator (of tariffs or rent controls), or as a resource in emergencies (such as tornadoes).