Final answer:
All the given options - economic situation, genetic family history, good nutrition, and physical activity and interaction - influence infant brain development. The answer cannot be determined accurately due to a missing option.
Step-by-step explanation:
The question asks which factor is NOT an influence on brain development in infants. Out of the options provided, economic situation of the family, genetic family history, good nutrition, and physical activity and interaction are all influences on brain development. Typically, a child's exposure to diverse environments and experiences, such as physical activities and social interactions, contribute significantly to brain development. However, there may be a missing option that is not listed, which does not play a role in influencing brain development. Without the complete list of options, specifically the missing 'C' option, it's not feasible to provide an accurate answer to the question. Factors like genetics, environment, and nutrition all play critical roles in shaping how the brain develops during infancy.