What will be the output of the following code: let x = 10; { let x = 20; } console.log(x);?

Which keyword is used to declare a read-only named constant?

A). let

B). var

C). const

D). static

What happens if you try to access a let variable before its declaration?

A). Returns undefined

B). Throws a ReferenceError

C). Returns null

D). Returns an empty string

What is the primary difference between var and let?

A). Scope

B). Initialization

C). Data type

D). Assignment

What will the following code output: { const a = 10; a = 20; }?

A). 10

B). 20

C). undefined

D). TypeError

What is the scope of a variable declared with let?

A). Global

B). Function

C). Block

D). Object

Can const be used for objects and arrays?

A). No

B). Yes

C). Only for arrays

D). Only for objects

Which keyword should be used for a variable that might be reassigned?

A). const

B). let

C). var

D). function

Which keyword allows block-level scope in ES6?

A). var

B). let

C). function

D). var and function

Can a let variable be redeclared in the same scope?

A). Yes

B). No

C). Only if it is a string

D). Only if it is a number

What will the following code output: { let y = 5; { let y = 10; console.log(y); } }?

A). 5

B). 10

C). undefined

D). ReferenceError