Which keyword should be used by default to declare variables in modern JavaScript?

Which of the following statements is true about 'const'?

A). It allows re-declaration

B). It allows reassignment

C). It is block-scoped

D). It is function-scoped

Can 'const' be used to declare an array or object?

A). No, only primitives

B). Yes, but the reference can't change

C). Yes, and the content can't change

D). No

What will be the output of the following code: let y = 10; let y = 20; console.log(y);

A). 10

B). 20

C). Error

D). undefined

How does 'let' handle variable re-declaration in the same scope?

A). Allows it

B). Silently ignores

C). Throws an error

D). Creates a new variable

How does 'let' differ from 'var' in terms of scope?

A). No difference

B). Function-scoped

C). Block-scoped

D). Global-scoped

Can you re-declare a variable using 'const' in the same scope?

A). Yes

B). No

C). Only in functions

D). Only in loops

What will happen if you declare a variable without 'var', 'let', or 'const'?

A). Creates a global variable

B). Creates a block-scoped variable

C). Creates a function-scoped variable

D). Throws an error

What will be the output of the following code: let c = 70; { let c = 80; console.log(c); } console.log(c);

A). 70 80 80

B). 80 80

C). Error

D). 70 80

Which keyword allows block-scoped variable declaration?

A). var

B). let

C). const

D). Both B and C

What will be the output of the following code: if (true) { let b = 60; } console.log(b);

A). 60

B). undefined

C). Error

D). null