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

Which of the following is a reserved word in JavaScript?

A). myVariable

B). function

C). let

D). number

Which identifier is valid in strict mode?

A). public

B). _public

C). 123public

D). public$

What will be the result of using a reserved word as an identifier?

A). No error

B). Syntax error

C). Logical error

D). Runtime error

Can identifiers start with a digit in JavaScript?

A). Yes

B). No

C). Only in ES5

D). Only in strict mode

Which of these is an invalid identifier?

A). foo_bar

B). fooBar

C). foo-bar

D). foo$bar

Can JavaScript identifiers include spaces?

A). Yes

B). No

C). Only in ES6

D). Only in strings

Are JavaScript identifiers case-sensitive?

A). Yes

B). No

C). Only in ES6

D). Only in strict mode

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

What is a valid identifier in JavaScript?

A). 123abc

B). abc123

C). let

D). var