Which characters are allowed in JavaScript identifiers?

Which of the following is a valid identifier?

A). if

B). else

C). null

D). value1

What is the maximum length of an identifier?

A). 255 characters

B). 31 characters

C). 64 characters

D). No limit

What is a valid identifier in JavaScript?

A). 123abc

B). abc123

C). let

D). var

Which identifier is valid in strict mode?

A). public

B). _public

C). 123public

D). public$

Which of the following is a valid identifier name?

A). var

B). 123abc

C). _123abc

D). #abc123

Can an identifier be a single character?

A). Yes

B). No

C). Only in ES5

D). Only in ES6

Which is a correct identifier for a variable?

A). 9variable

B). variable-9

C). variable_9

D). variable 9

Is let a valid identifier in JavaScript?

A). Yes

B). No

C). Only in ES6

D). Only in non-strict mode

What will happen if you declare a variable with the name undefined?

A). Syntax error

B). Declares a variable

C). Throws a runtime error

D). Reassigns undefined

What is the output of the following code: var x = 5, x = 10;

A). Syntax error

B). 5

C). 10

D). Reference error