Concept:Parallel databases are built to improve speed, uptime, and safety, but they are harder to manage.
Explanation:Parallel databases split work across multiple processors to achieve high performance.
They also provide high availability, meaning the database stays accessible even if one part fails.
Reliability is another benefit, because data is stored and processed redundantly to prevent loss.
These features make parallel databases faster and more dependable than single-processor systems.
However, complexity is not a benefit. It is a serious drawback.
Setting up a parallel database requires careful data distribution and coordination of parallel queries.
This adds difficulty for administrators and increases maintenance effort.
Thus, high performance, availability, and reliability are benefits, while complexity is not.
Answer:D. complexity