What does the Symbol data type represent in JavaScript?
A). A unique identifier
B). A number
C). A boolean value
D). An object
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 statements about primitive values in JavaScript is true?
A). They are mutable
B). They are passed by reference
C). They are stored on the heap
D). They are immutable
Which of the following is a primitive data type in JavaScript?
A). Array
B). Object
C). Function
D). String
What is the default value of a variable in JavaScript if it is not initialized?
A). null
B). undefined
C). 0
D). 'undefined'
Which symbol is used to represent a boolean value in JavaScript?
A). #
B). $
C). !
D). true/false
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 NaN in JavaScript?
A). Number
B). String
C). Object
D). Undefined
Which of the following is not a primitive value in JavaScript?
A). Number
B). Boolean
C). Object
D). String
Which of the following statements is true about JavaScript's null value?
A). It represents an empty string
B). It represents a non-existent value
C). It represents a boolean value
D). It represents a number