Answer:
d. increased passport security at internal borders
Step-by-step explanation:
The European Union is the union created between 28 european states with the goal of promoting peace, have a single economic system and remove borders and trade barriers between them. So, as the borders between the states were removed, people can move freely between the member states without needing a passport. Because of that, increased passport security at internal borders is not an effect of the creation of the European Union.