The let keyword can be used

A. in a for or for/in loop, as a substitute for var

B. as a block statement, to define new variables

C. to define variables that are scoped to a single expression

D. all of the mentioned

Solution(By Examveda Team)

The let keyword can be used in four ways :
1. as a variable declaration like var;
2. in a for or for/in loop, as a substitute for var;
3. as a block statement, to define new variables and explicitly delimit their scope; and
4. to define variables that are scoped to a single expression.