What is the effect of the static keyword for a local variable inside a function?

• A. It makes the variable global
• B. It allocates stack memory
• C. It disables optimization
• D. It gives the variable static storage duration, preserving its value between calls

Answer: (D)

Static local variables have static storage duration, which means the variable exists for the entire run of the program and preserves its value between function calls. The function’s scope stays local to that function, so it isn’t accessible from outside, but its memory isn’t released after the function returns. Initialization happens only once (on the first call, or at program start if given a constant initializer), and later calls see the value left from the previous call. It’s not global, and it isn’t allocated on the per-call stack, which is why the value persists.