Which of the Following Observations Is an Example of an Inverse

Which of the following observations is an example of an inverse correlation?

A) As a population's intake of beta-carotene increases,the population's tissue levels of vitamin A increase.
B) Children who consume 3 cups of vitamin D milk daily develop stronger bones than children who drink fewer than 3 cups of vitamin D milk each day.
C) When population increases its daily consumption of whole-grain products,the population's frequency of daily bowel movements increases.
D) Women who smoke 5 or more cigarettes each day during pregnancy are more likely to give birth to underweight babies than women who smoke fewer than 5 cigarettes a day during pregnancy.