In which theory is it of utmost importance that an infant develops a relationship with at least one primary caregiver for both social and emotional development to happen properly?

A. Attachment theory
B. Culture
C. Persistence model
D. Erikson’s Stages of Psychosocial Development
my answer is D. Am I correct?

Right.

No, the correct answer is A. Attachment theory. In this theory, it is believed that infants need to form a secure attachment to at least one primary caregiver in order to develop socially and emotionally. To arrive at this answer, you could have eliminated options B and C since they are not related to infant development theories. This would have left you with options A and D. To differentiate between them, you could have remembered that Erikson's Stages of Psychosocial Development cover a broad range of developmental areas across the entire lifespan, whereas attachment theory specifically focuses on the early stages of development. Therefore, the correct answer is A.