Which is right?

Question

When linking css stylesheet...

<link rel="stylesheet" type="text/css" href="css/style.css">
<link rel="stylesheet" type="text/css" href="css/style.css" />
<link rel="stylesheet" href="css/style.css">

Sometimes a forward slash is included at the end.
Or sometimes type is left out.

Answer 1

In some tags the final slash is optional
As in
<link>
<input>
<br>
<hr>