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
What does the expression typeof 42 return in JavaScript?
A). number
B). string
C). undefined
D). boolean
Which primitive data type represents variables that have been explicitly set to represent no value?
A). Number
B). String
C). Undefined
D). Null
Which primitive data type represents variables that are declared but not initialized?
A). Number
B). String
C). Undefined
D). Null
What does the expression typeof '123' return in JavaScript?
A). number
B). string
C). undefined
D). boolean
What does the expression typeof true return in JavaScript?
A). number
B). string
C). boolean
D). undefined
Which data type represents variables that have been explicitly set to have no value?
A). Number
B). Undefined
C). String
D). Null
What is the result of the expression typeof undefined in JavaScript?
A). number
B). string
C). undefined
D). boolean
What does the expression typeof Symbol() return in JavaScript?
A). number
B). string
C). symbol
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