Final answer:
One of the earliest business applications of information systems was payroll processing, which utilized early computing technology to automate repetitive calculations and data management for employee payments.
Step-by-step explanation:
The question relates to the history of information systems and their early applications in business. Among the choices provided, one of the very first business applications of information systems was A) Payroll processing. This application became an early use of computing technology because handling payrolls involved repetitive calculations and data management that could be automated with the use of computers. While inventory management, email communication, and word processing were also important, payroll processing often took precedence as a starting application given the critical nature of timely and accurate payment calculations for employees.