Which of the following is an effect of social reforms of the 19th and 20th centuries?
a) agricultural output decrease
b) the population density in urban centers decreased
c) the length of a normal work day increased
d) the life expectancy for children increased

Option C.

An effect of social reforms of the 19th and 20th centuries is the length of a normal work day increased.

Explanation:

In the nineteenth and twentieth century, many industrial and urbanization reforms were achieved as a result of which the length of normal work day increased.The agricultural sector also developed rapidly and its outputs increased by the introduction of modern methods and techniques in the agriculture sector.The population in the urban centers started to increase. However, the life expectancy of children decreased.  

The correct answer is kettles.