What will be the output of the following code?

let a = 1; let b = 2; let c = a + b; console.log(c);

Which keyword should be used to declare a block-scoped variable?

A). var

B). let

C). const

D). Both let and const

Which of the following is a valid variable name in JavaScript?

A). 2name

B). _name

C). #name

D).

What will be the output of the following code?

const a = 10; a = 20; console.log(a);

A). 10

B). 20

C). Error

D). undefined

What is hoisting in JavaScript?

A). Function call before declaration

B). Variable declared at the top

C). Variable and function declaration are moved to the top

D). Variable scope

Can you reassign a value to a variable declared with let?

A). Yes

B). No

C). Only in strict mode

D). Only inside a block

Which of the following is true about 'const' variables in JavaScript?

A). They can be redeclared

B). They cannot be reassigned

C). They can be reassigned

D). They are always undefined

What will be the output of the following code?

var a = 1; { var a = 2; } console.log(a);

A). 1

B). 2

C). undefined

D). ReferenceError

Which of the following will cause an error?

A). let a = 10; a = 20;

B). const a = 10; a = 20;

C). var a = 10; a = 20;

D). None of the above

What will be the output of the following code?

console.log(a); var a = 10;

A). 10

B). undefined

C). Error

D). null

Which of the following is correct about variable scope in JavaScript?

A). var is block-scoped

B). let is function-scoped

C). const is block-scoped

D). All variables are global