Which primitive data type represents variables that have been explicitly set to represent no value?

What does the expression typeof '123' return in JavaScript?

A). number

B). string

C). undefined

D). boolean

How is the Symbol data type different from other primitive data types in JavaScript?

A). Symbols can be used as object keys

B). Symbols can be compared directly

C). Symbols can be used in mathematical operations

D). Symbols can be concatenated with strings

Which primitive data type represents variables that are declared but not initialized?

A). Number

B). String

C). Undefined

D). Null

Which primitive data type represents unique identifiers introduced in ECMAScript 6?

A). Number

B). Symbol

C). Boolean

D). Undefined

Which of the following statements accurately describes the Boolean data type in JavaScript?

A). It represents textual data

B). It represents numeric data

C). It represents logical values

D). It represents an absence of value

What is the result of the expression typeof undefined in JavaScript?

A). number

B). string

C). undefined

D). boolean

What does the expression typeof 42 return in JavaScript?

A). number

B). string

C). undefined

D). boolean

Which data type is represented by the value null in JavaScript?

A). Numeric data

B). Textual data

C). Absence of value

D). Logical value

What does the expression typeof Symbol() return in JavaScript?

A). number

B). string

C). symbol

D). boolean

What is the result of the expression typeof 'Hello' in JavaScript?

A). number

B). string

C). undefined

D). boolean