The infrastructure of an area can determine what kind of economic activity goes on there. all of these are examples of elements of an infrastructure except
a) a sewer system
b) a network of roads
c) widespread and reliable electrification
d) a population of skilled and unskilled labor

The answer which is not an elements of an infrastructure is:

D)a population of skilled and unskilled labor

Explanation: Population of skilled and unskilled labor is not a criteria or not an element of infrastructure because infrastructure is the basic physical and organizational structures and facilities of an area.

a tornado is in the image above.