Which of the Following Statements Is the BEST Example of a Hypothesis

Which of the following statements is the BEST example of a hypothesis about human development?

A) Cross-cultural studies have determined that human breast milk provides the ideal nutrition for infant brain development.
B) Human breast milk contains nutrients that are essential for formation of neurons and synapses in an infant's developing brain.
C) Because human breast milk is a superior form of nutrition for infants, all newly-delivered women should be encouraged to breast feed their infants.
D) If breast milk is a superior supplement for infant brain development, children who were breast-fed as infants should perform better on psychological tests than children who were not breast fed.