Which symbol is used to represent a boolean value in JavaScript?

Which of the following statements is true about primitive data types in JavaScript?

A). They have methods and properties

B). They can be used as keys in objects

C). They are instances of Object

D). They are passed by value

What happens when you try to access a variable that has not been declared in JavaScript?

A). SyntaxError is thrown

B). ReferenceError is thrown

C). TypeError is thrown

D). Undefined

Which of the following is a valid JavaScript symbol?

A). symbol

B). &symbol

C). #symbol

D). Symbol('description')

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

A). String

B). Object

C). Undefined

D). Number

What is the result of the expression undefined + null in JavaScript?

A). undefined

B). null

C). 0

D). Error

What is the result of the expression 5 + '5' in JavaScript?

A). 10

B). '55'

C). '10'

D). Error

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

A). Array

B). Object

C). Function

D). String

What is a primitive value in JavaScript?

A). A complex data structure

B). A basic data type

C). A function

D). An array

What does the Symbol data type represent in JavaScript?

A). A unique identifier

B). A number

C). A boolean value

D). An object

What is the default value of a variable in JavaScript if it is not initialized?

A). null

B). undefined

C). 0

D). 'undefined'