What economic philosophy advocates for the removal of regulatory barriers and is associated with the 40th president of the United States?

Supply-side economics is an economic philosophy that emphasizes the importance of boosting economic growth by reducing taxes and decreasing regulation. This approach suggests that when individuals and businesses have more disposable income due to lower taxes and fewer regulatory barriers, they are more likely to invest in the economy, leading to job creation and overall economic expansion.

The philosophy gained prominence during the presidency of Ronald Reagan, the 40th president of the United States, who implemented many of these principles through tax cuts and deregulation in the 1980s. Supporters argue that supply-side policies can lead to greater economic efficiency and, in the long run, increased government revenue despite lower tax rates.

In this context, it is evident how supply-side economics aligns with the idea of promoting economic growth through lower regulatory barriers and tax reductions, marking it as the correct answer to the question.