What is the primary reason a variable defined inside a function cannot be accessed outside of that function?

The primary reason a variable defined inside a function cannot be accessed outside of that function is due to local scope. When a variable is declared inside a function, it is confined to that specific function's scope, meaning it is only available and recognized within that function. This is a fundamental concept in programming that helps maintain the integrity of a function’s operation by preventing external code from inadvertently manipulating its internal state.

Local scope ensures that the variable can only be used within the context of its function, avoiding naming conflicts and unintended interactions with variables of the same name outside the function. This encapsulation allows for cleaner and more modular code, as each function can operate independently without concern for the rest of the program's variables.

In contrast, variables defined in the global scope would be accessible from anywhere in the program, which is not the case for those declared within a function. The other options describe scenarios that do not relate to scope directly, emphasizing that local scope is the key reason for the limitation on access to those function-specific variables.