Which keyword in JavaScript can declare variables in a block scope?

The correct choice is based on the understanding of scope in JavaScript. The keyword that declares variables in a block scope is "let". When a variable is defined using the let keyword, it is limited to the block, statement, or expression in which it is used. This means that the variable cannot be accessed outside of that block, making it a useful way to manage variable scope and avoid unintended interference from variables defined in other parts of the code.

For example, if a variable is declared inside an if statement or a for loop using let, it will only be available within that specific block. This behavior helps in minimizing potential scope-related bugs and enhances code readability and maintainability.

In contrast, the var keyword does not have block scope—variables declared with var can be accessed outside of their immediate block, which can lead to errors if not carefully managed. The const keyword also declares constants using block scope, but since the question specifically asks for variable declaration, let is the most appropriate answer. The static keyword is not related to variable scope in JavaScript but is instead used in other contexts, such as in class declarations.