What does "high-level" refer to when discussing programming languages?

"High-level" programming languages are designed to be easy for humans to read and write, resembling natural languages more closely than machine code. This means that these languages abstract away much of the complex details of the computer's hardware, allowing programmers to focus more on problem-solving and the logic of their code rather than the intricacies of the machine's architecture.

High-level languages often include features like clear syntax, strong data type abstractions, and built-in functions that make it simpler for developers to read and understand what the code is meant to do without needing to grasp the underlying binary code or low-level machine instructions. This abstraction contributes to increased productivity and ease of learning, which is a hallmark of high-level programming languages.

The other options relate to different aspects of programming language design. Execution speed refers to how fast a program runs, which can vary widely among languages. The amount of machine control relates to how closely a language allows a programmer to interact with hardware, which is generally lower in high-level languages compared to low-level languages. Lastly, the complexity of syntax can be present in both high-level and low-level languages; complexity doesn’t necessarily correlate with the "high-level" classification, which primarily focuses on ease of human understanding.