According to Freudian Psychoanalytic Theory, a Child May Become Fixated

According to Freudian psychoanalytic theory, a child may become fixated in the oral stage of development. In Freud's view, what experience can lead to this type of fixation?

A) a stringent potty-training schedule
B) concentrating on schoolwork too long
C) playing with opposite-gender children too often
D) being denied appropriate amount of breast milk or nursed too long