I saw several website which do not close meta tag and also saw several site which close meta tag. like other HTML Tag, closing of meta tag is mandatory? or it optional?

<meta name="viewport" content="width=device-width, initial-scale=1.0,minimal-ui">

OR

<meta name="viewport" content="width=device-width, initial-scale=1.0,minimal-ui" />

OR

<meta name="viewport" content="width=device-width, initial-scale=1.0,minimal-ui"> </meta>

Which one is correct and recommended?

Note : my question is about Meta tag. i know all other HTML tag need closer but META Tag is confusing. so, do not close my question by false marking duplicate.