Which data type represents unique and immutable values in JavaScript introduced in ES6?

What will the following code snippet output: let a = 10; a += '5'; console.log(a); in JavaScript?

A). '105'

B). 105

C). 15

D). '15'

What will let x = '10'; let y = x - 5; console.log(y); output in JavaScript?

A). '5'

B). 5

C). '10'

D). 10

What is the outcome of typeof undefined in JavaScript?

A). String

B). Undefined

C). Null

D). Number

What is the data type of the value true in JavaScript?

A). Number

B). String

C). Boolean

D). Undefined

What is the outcome of typeof [1, 2, 3] in JavaScript?

A). String

B). Number

C). Array

D). Object

Which data type represents a block of reusable code in JavaScript?

A). String

B). Object

C). Function

D). Number

What will be the result of typeof 'hello' in JavaScript?

A). String

B). Number

C). Undefined

D). Function

Which of the following is not a valid data type in JavaScript?

A). Array

B). Symbol

C). Map

D). Tuple

What does NaN represent in JavaScript?

A). Not a Number

B). Infinity

C). Positive Infinity

D). Negative Infinity

Which data type represents positive infinity in JavaScript?

A). Infinity

B). Number

C). NaN

D). Null