Final answer:
Klein believed that during the female Oedipus complex, the girl fantasizes that b) Her mother is a rival.
Step-by-step explanation:
In the female Oedipus complex, proposed by psychologist Melanie Klein, the girl fantasizes that her mother is a rival. This means that she sees her mother as a competitor for the attention and affection of her father. This rivalry arises from the girl's desire to possess her father exclusively and to take her mother's place in his affections.
For example, a girl may feel jealous when her father spends time with her mother or when her mother shows affection towards her father. This jealousy and rivalry can lead to feelings of anger and frustration towards the mother.
Overall, the female Oedipus complex involves complex and conflicting emotions and desires in a girl's relationship with her parents. The correct answer is b) Her mother is a rival.