What contributed to the postwar construction boom? a. prices for labor and material were high. b. builders lacked mass-production techniques. c. the wide availability of low cost mortgages for african americans. d. few houses were built during the great depression.

The correct answer is D.

The first two statements represent factors that would cause construction of homes to decrease, not increase.

Statement C is also incorrect because many African-Americans were denied mortgages after World War II. Banks would refuse to give low cost mortgages to African-Americans even though they served in the US military. Along with this, African-Americans were also excluded from many suburban neighborhoods, showing that they were not the target audience of this construction boom.

This shows that D is the correct answer. This makes sense, as the Great Depression was an era in which hundreds of thousands of Americans became homeless and could not afford to buy a new house. Since not many people were able to afford new homes, they were not built.