Final answer:
According to Freud's psychoanalytic theory, the phallic stage is most likely to result in fixations associated with passive or aggressive behavior.
Step-by-step explanation:
The stage most likely to contribute to fixations involving becoming very passive or very aggressive, according to psychoanalytic theory, is the phallic stage. During this stage, the child's erogenous zone is the genitals, and the resolution of the Oedipus complex for boys and the Electra complex for girls is critical for healthy psychological development. Fixation at this stage can result in a personality that might display extreme vanity and ambition or can lead to passive or aggressive behavior.