Final answer:
The move of retail banking to use ATMs after Citibank unveiled its first ATMs illustrates the use of information systems to achieve improved efficiency.
Step-by-step explanation:
The move of retail banking to use ATMs after Citibank unveiled its first ATMs illustrates the use of information systems to achieve improved efficiency. By introducing ATMs, Citibank was able to automate banking processes and reduce the need for staff and physical branches, leading to faster and more convenient banking services for customers. The use of ATMs improved the efficiency of retail banking operations, allowing the bank to provide services to a larger number of customers with fewer resources.