For each of the following, determine whether inflation expectations, demand-pull inflation, or cost-push inflationand hence inflation overallwill change.

a. A rapid influx of foreign investment causes the output gap to become more positive.

b. The president unexpectedly announces a tariff on aluminum and steel.

Make the detailed explanation and analysis. With the knowledge of "The Phillips Curve and Inflation" in Macroeconomics.

Thank you so much.