During World War II, unemployment in the U. S. declined and the gross national product increased because.

A. U. S. manufacturers received huge defense contracts and reopened factories.

B. most adult males in the U. S. found employment in the military or military production industries.

C. automobile and textile factories reopened to produce jeeps, tanks, and military uniforms.

D. All of these choices are correct.

All the given factors are responsible for unemployment in the U. S. declined and the gross national product increased during World War II.

Option: D

Explanation:

There was a desperate need for military personnel and wartime necessities due to the rising demand for greater war production on the home front, labor mobilization under state mandate achieved a new high for Americans throughout World War II.

In this struggle for limited human resources, the government crafted strategies to meet the armed forces and the economy's numerous and overlapping demands for manpower. The manufacturing industries were ordered to provide military tanks and trucks, which raised huge employment and opportunities to structure new business for war reasons as well as to streamline the process owing to their overall participation due to the wider availability of personnel.

All of these choices are correct for the increase in the gross national product (GNP) of US during world war ll.

Explanation:

During world war 2 the world economy was dropping down due to the money spent in the war and other military activities but in the US their participation in the war increased their economic status and also resulted in the reduction of the unemployment rate. The manufacturing industries were instructed to provide the military tanks and trucks for war purposes and also due to the more availability of manpower the process was speeded up by their total involvement. Most of them got employed in the US military for the various works and people too contributed by decreasing their usage and lending them to the military expenditure starting from the milk, food and leather etc ..., Thus the US get benefitted in the world war with the economy and employment rate.