Which of the following represents a component of aggregate demand?

Aggregate demand refers to the total demand for all goods and services within an economy at a given overall price level and in a given time period. It is composed of various components, including consumer spending, business investments, government spending, and net exports (exports minus imports).

Federal government purchases are a key component of aggregate demand because they include all spending on goods and services by the government, which directly influences overall economic activity. When the government increases its purchases, it injects money into the economy, stimulating demand for goods and services. This not only affects the levels of consumption and investment in the economy but also leads to employment and income generation.

On the other hand, net income from foreign sources pertains to international investment earnings, commercial bank stocks are related to the financial markets rather than direct economic consumption, and individual personal savings represent money that is not being spent, thus not directly contributing to aggregate demand. Therefore, federal government purchases stand out as the correct answer as they are a direct and significant factor in the measurement and impact of aggregate demand.