Choose ONE correct answer from the four options.
What is the aim of the following sentence?
Because the goal of the study was to examine typical brain development, only infants who experienced a normal, uncomplicated birth and a normal course of development were included.
A、To explain how the subjects were selected
B、To indicate the importance of studying infants
C、To emphasize the novelty of the research design
D、To demonstrate the contribution of the research subject