What is the difference between var, let, and const in terms of scope?

The distinction between var, let, and const primarily revolves around their scope, and option three accurately captures this nuance.

Var is indeed function-scoped, meaning that if it is declared inside a function, it is accessible throughout that function. However, if it is declared outside any function, it becomes globally scoped and can be accessed throughout the entire script.

In contrast, both let and const are block-scoped. This means that they are only accessible within the nearest enclosing block (enclosed by curly braces {}), such as within loops, conditionals, or any other block structure. This block scoping provides tighter control over variable visibility, helping to avoid unintentional changes or conflicts that can occur when variables are accessible more widely than intended.

Therefore, option three correctly identifies that var is function-scoped while let and const are restricted to the block in which they are defined. This understanding is essential for effectively managing variable scope in JavaScript, particularly in more complex applications where function nesting and block structures are common.