The correct answer is: B. is necessary on all systems, regardless of how good
System maintenance is the process of keeping a system in good working order. It includes tasks such as updating software, fixing bugs, and adding new features. System maintenance is necessary on all systems, regardless of how good they are. Even the best systems will eventually need to be updated or fixed.
Option A is incorrect because system maintenance is always necessary, regardless of how good the system is.
Option C is incorrect because system maintenance is always necessary, even if the system is well written.
Option D is incorrect because system maintenance can be done with a single program, or with multiple programs depending on the complexity of the system.
Option E is incorrect because system maintenance is always necessary.