Net imbalance between injections and leakages causes short-run disequilibrium

Steps:

• Injections consist of investment (I), government spending (G), and exports (X); leakages consist of savings (S), taxes (T), and imports (M).
• Equilibrium requires total injections equal total leakages.
• Disequilibrium occurs when changes create an unmatched surplus or deficit in these flows.
• Evaluate each option for net effect on injections relative to leakages.

Why B is correct:

• Boosts injections by $60bn ($30bn I + $30bn G) with no leakage offset, violating injection-leakage equality in the circular flow model.

Why the others are wrong:

• A: G rise ($10bn injection) exactly offsets X fall ($10bn injection), preserving balance.
• C: T rise ($40bnleakage)cutsdispos$40bn leakage) and limiting net imbalance.

Final answer: B