Which data type represents an intentional absence of any value in JavaScript?

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'

Which of these is a complex or reference data type in JavaScript?

A). Number

B). Boolean

C). Object

D). String

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

A). Symbol

B). Object

C). Array

D). Function

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

What is the outcome of typeof undefined in JavaScript?

A). String

B). Undefined

C). Null

D). Number

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

A). '5'

B). 5

C). '10'

D). 10

What will let x = null; console.log(typeof x); output in JavaScript?

A). Object

B). Null

C). Undefined

D). Number

What is the data type of the value 42 in JavaScript?

A). String

B). Boolean

C). Number

D). Null

Which operator checks if an object is an instance of a specific object type in JavaScript?

A). instanceof

B). typeof

C). isInstanceof

D). isTypeOf