Which of the following policies can assist a country to reduce unemployment in a short period of time?

Increasing the investment in both public and private sector

Increase in investments lead to an increase in GDP of the country, since investment is a component of National Income. With an increase in overall GDP, aggregate demand will increase in short term, leading to excess demand in the economy. To meet excess demand in the economy, more output is needed, thus for that more labour needs to be hired. This whole process results in increase in employment.