$10 billion gov’t spending increase with MPC 0.9 raises AD by:

Higher tax rates typically reduce disposable income for consumers and decrease profits for businesses, leading to lower consumption and investment. This would actually result in a leftward shift of the AD curve, not a rightward one, as both consumer spending and business investment decline.

Higher production costs lead to decreased profitability for firms, which may reduce their output and investment. This translates into lower aggregate demand as firms scale back on production and consumers may face higher prices. Thus, higher production costs would shift the AD curve to the left rather than to the right.

Higher imports can lead to a decrease in domestic demand for local goods, as more products are sourced from abroad. This shift would detract from the overall demand for domestic goods and services, resulting in a leftward shift in the AD curve, contradicting the rightward movement indicated in the question.