d. All of the options are involved in systems study:
a. Design of system: This involves creating a plan or blueprint for how the system will be constructed, including its components, processes, and interactions.
b. Determination of system requirements: This involves identifying the needs and constraints of the system, including the functional and non-functional requirements, as well as any legal or ethical considerations.
c. System testing: This involves evaluating the system to ensure that it meets the requirements and functions correctly, including performance testing, security testing, and usability testing.
All of these options are critical to a comprehensive systems study, as they help ensure that the system is designed, built, and tested to meet the needs and expectations of its users.