Using Fonts

What is the right way to connect a font using a link?

A)

@font-face { 
  src: url('https://fonts.googleapis.com/css2?family=Pattaya&display=swap');
}

B)

.block { 
  font-family: url('https://fonts.googleapis.com/css2?family=Pattaya&display=swap'); 
}

C)

@import url('https://fonts.googleapis.com/css2?family=Pattaya&display=swap');

D)

.block {  
  @font-family { 
    url('https://fonts.googleapis.com/css2?family=Pattaya&display=swap'); 
  }
}