Which characters are allowed in JavaScript identifiers?

Which of the following is an invalid identifier?

A). _variable

B). var$

C). 2variable

D). variable2

Which identifier is valid in strict mode?

A). public

B). _public

C). 123public

D). public$

What does the following code do: var $ = 5;

A). Throws an error

B). Creates a variable named $

C). Creates a variable named var

D). None of the above

Are JavaScript identifiers case-sensitive?

A). Yes

B). No

C). Only in ES6

D). Only in strict mode

Can an identifier be a single character?

A). Yes

B). No

C). Only in ES5

D). Only in ES6

What is the maximum length of an identifier?

A). 255 characters

B). 31 characters

C). 64 characters

D). No limit

What will the following code output: var x; x = 5; var y = x;

A). undefined

B). null

C). 5

D). x

Can identifiers start with a digit in JavaScript?

A). Yes

B). No

C). Only in ES5

D). Only in strict mode

Which of the following is a valid identifier?

A). if

B). else

C). null

D). value1

Which of the following is a reserved word in JavaScript?

A). myVariable

B). function

C). let

D). number