Final answer:
The correct sequence in the functional model of an information system is Input, Processing, Output, Users, representing the complete data processing cycle.
Step-by-step explanation:
The functional model of an information system is typically represented by the sequence of components involved in the data processing cycle. This sequence begins with Input, where data is collected and entered into the system. The next step is Processing, which refers to the various operations and transformations that the data undergoes to convert it into useful information. Following this is Output, where the processed information is presented in a usable form. Lastly, Users interact with the system to input data and interpret the output information. Therefore, the correct sequence in the functional model of an information system is B. Input, Processing, Output, Users.