Final answer:
Dress code in schools is not a broad social or economic change impacting careers in early childhood education, unlike the other options listed.
Step-by-step explanation:
The option that is not a social or economic change which has impacted careers in early childhood education is c. dress code in schools. Growing cultural diversity (a) and changes in family structures (b) are significant factors that directly influence the demands and practices within early childhood education. The increasing cost of child care (d) is an economic factor that affects both the options available to families and the economic viability of early childhood education as a career. Dress codes in schools, however, are specific rules implemented at the institution level and do not represent a broader social or economic change impacting early childhood careers.