The total fertility rate in country A was 6.8 in 1980. Which of the following statements best supports the change in the total fertility rate in country A between 1980 and 2015?
A) The total fertility rate increased as a result of improved health care and better nutrition.
B) The total fertility rate remained constant even though there was improved access to clean water.
C) The total fertility rate decreased as a result of a delay in age of first marriage and increased contraceptive use.
D) The total fertility rate decreased as a result of increased infant mortality rate.
