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

Which of the following is a valid identifier name?

A). var

B). 123abc

C). _123abc

D). #abc123

Which is a correct identifier for a variable?

A). 9variable

B). variable-9

C). variable_9

D). variable 9

Which characters are allowed in JavaScript identifiers?

A). Letters only

B). Letters and numbers only

C). Letters, numbers, $ and _

D). Any special characters

Which of these is an invalid identifier?

A). foo_bar

B). fooBar

C). foo-bar

D). foo$bar

What is the maximum length of an identifier?

A). 255 characters

B). 31 characters

C). 64 characters

D). No limit

Can JavaScript identifiers include spaces?

A). Yes

B). No

C). Only in ES6

D). Only in strings

Which of the following is an invalid identifier?

A). _variable

B). var$

C). 2variable

D). variable2

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 reserved word in JavaScript?

A). myVariable

B). function

C). let

D). number

Which of the following is a valid identifier?

A). if

B). else

C). null

D). value1