Investment tax credit increases economic growth by:

Raising taxes would likely reduce disposable income for consumers, leading to decreased spending and potentially further economic contraction. This approach counteracts the goal of stimulating the economy and can exacerbate unemployment, rather than address the issues associated with operating below full employment.

Cutting spending can lead to a decrease in overall demand within the economy. When government or consumer spending is reduced, it can result in layoffs and a slowdown in economic activity, worsening the situation of an economy that is already below full employment.

Increasing the reserve ratio requires banks to hold more reserves and reduces the amount of money available for lending. This contractionary measure can limit investment and spending in the economy, which is counterproductive when the goal is to restore equilibrium and reduce unemployment.