During the 1950s, an increase in the number of marriages and births fueled

During the 1950s, an increase in the number of marriages and births fueled a demand for housing.

People who was born in the 1950s were known as the baby boomers. The increasing number of marrieages and births in population of post-World War II  led to an increase in the demand for housing and gave rise to higher density cities.

By the 1970s, the United States economy had grown by leaps and bounds and was by far the largest economy in the world.

(C)

Explanation: a demand for housing.

a. because the u.s. was the leading with the most technology, economy, etc. also was teamed with other allies witch boosted the economy and materials to improve technology and use it.