Which statement is true regarding functional programming languages?

Functional programming languages are indeed classified as high-level languages. This classification indicates that they provide strong abstraction from the details of the computer's hardware, allowing developers to express complex concepts in a more understandable and manageable way. In functional programming, computation is treated as the evaluation of mathematical functions and avoids changing state or mutable data, which aligns well with high-level programming paradigms.

High-level languages usually offer features that help with code readability, maintainability, and ease of use, which are characteristics prevalent in functional programming languages such as Haskell, Lisp, or Erlang. These languages often incorporate advanced features such as first-class functions, higher-order functions, and lazy evaluation, further demonstrating their high-level nature.

The other options do not accurately describe the nature of functional programming languages. They are generally not associated with system programming, since lower-level, more performance-sensitive languages such as C or C++ tend to be preferred for that purpose. Additionally, functional programming often utilizes automatic memory management through garbage collection rather than requiring manual memory management, distinguishing them from many traditional languages that do. Finally, functional programming languages are considered high-level rather than low-level, which typically involve direct manipulation of memory and hardware resources.