Which storage class specifier in C allows a local variable to retain its value between successive function calls, while keeping its scope limited to the function in which it is declared?

A variable declared with the static keyword inside a function is initialized only once and retains its value across multiple calls to that function, while remaining accessible only within that function's scope. auto is the default storage class for local variables, which are recreated on each call. extern declares a variable defined elsewhere, typically for sharing across files. register hints at storing a variable in a CPU register without affecting its lifetime, and volatile tells the compiler a variable may change unexpectedly, but does not affect its lifetime.