Which shape does the CSS rule in style.css give to images?

A square with rounded cornersA circleA wide rectangle A square with sharp corners<html>
  <head>
  <style>
img {
width: 100px;
height: 100px;
border-radius: 20px;
}
  </style>
</head>
 <body>
  <h2>Tokyo Tours</h2>
  <img src="https://mimo.app/r/tokyo.png">
 </body>
</html>]]>

The image has the shape of a square with rounded corners.