The system comprises how many subsystems?

• A. 3
• B. 4
• C. 5
• D. 6

Answer: (B)

Count how many subsystems by identifying the major functional blocks that make up the system. Each block handles a distinct function and interfaces with the others at defined boundaries. In this item, the system is divided into four such functional areas, so there are four subsystems. The four blocks are the independent parts you can analyze or test separately, and the count should reflect those distinct functions rather than individual components within each block. If you relied on grouping parts without recognizing the four separate functional areas, you’d miscount. The key is to spot the four functional blocks that together form the whole system.