Final answer:
Freud believed that fixations in psychosexual development occur due to deprivation or overindulgence in pleasurable experiences, which can lead to certain behaviors and personality traits in adulthood. The correct answer is option 4.
Step-by-step explanation:
According to Freud, fixations occur throughout the psychosexual stages due to either deprivation or overindulgence in pleasurable experiences at a given stage. During the oral stage, for example, fixations might result from improper weaning, leading to behaviors such as smoking or overeating in adulthood. In the a_al stage, either overly strict or lenient toilet training can result in an a_al-retentive or a_al-expulsive personality, respectively. Similarly, during the phallic stage, unresolved Oedipus complex can result in a personality that is seen as vain and overly ambitious. If these stages are navigated successfully without fixations, an individual reaches the genital stage, where mature sexual interests develop into well-balanced, healthy adulthood.