What is the data type of the value undefined 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'

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

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

A). String

B). Object

C). Function

D). Number

Which of the following is a primitive data type in JavaScript?

A). Object

B). Array

C). Function

D). Boolean

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

A). Number

B). String

C). Boolean

D). Undefined

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

A). Object

B). Null

C). Undefined

D). Number

What does NaN represent in JavaScript?

A). Not a Number

B). Infinity

C). Positive Infinity

D). Negative Infinity

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

A). Number

B). Boolean

C). Object

D). String

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

A). Null

B). Undefined

C). String

D). Number