Final answer:
The ego is the rational part of our personality, balancing our primal urges and moral compass to behave appropriately in society. Hence, the answer is d. Ego.
Step-by-step explanation:
The question asks about the part of self that is considered the rational part. In psychological theory, particularly in the framework proposed by Sigmund Freud, the ego is the component of personality tasked with finding realistic ways to satisfy the id's desires, while also trying to meet the moralistic demands of the superego. The ego operates according to the reality principle, meaning that it helps us behave in ways that are rational and acceptable within the social context we find ourselves in. Therefore, the correct answer to the question is d. Ego.
Freud's model of the psyche is structured around three elements: the id, which is driven by primal urges; the superego, which acts as a moral compass; and the ego, which you can think of as the rational mediator between those two forces. The ego's job is to balance the two, ensuring that we can function appropriately in society. This explanation ties into both psychological theories and philosophical concepts on rationality and self-interest, such as rational egoism and ethical egoism.