The diagram below outlines the main injections and leakages (withdrawals) within the circular flow of income.
Based on this model of an open economy with a government sector, which of the following combinations of macroeconomic changes will unambiguously cause the level of national income to contract?
An increase in export sales and a reduction in tax rates
A decrease in domestic investment and an increase in household savings
An increase in government expenditure and an increase in import spending
A reduction in corporate tax rates and a decrease in export sales
