What is a key characteristic of the `let` keyword?

The let keyword in JavaScript is characterized primarily by its block-scoping nature. This means that any variable declared with let is scoped to the block in which it is defined, such as within a loop or an if statement. This differs significantly from variables declared with var, which are scoped to the function in which they are defined or globally scoped if they are declared outside of any function.

Being block-scoped allows for more predictable variable management, especially in cases where you want to limit the lifespan of a variable to a specific code block, thus reducing the likelihood of unintended behavior caused by variable hoisting or conflicts in larger codebases. This is a significant design choice by JavaScript to enhance readability and maintainability of the code.

In contrast, other options describe characteristics that do not apply to let. For instance, let variables cannot be redeclared in the same scope, making them more robust against variable shadowing compared to var. Additionally, let does not initialize variables to null; instead, they are in a "temporal dead zone" until they are defined. This distinction is crucial for developers to understand how variable scope and lifecycle are managed in their JavaScript code.