Convert the following temperatures to the Kelvin scale:
$(a)$ $25\,^{\circ}C$
$(b)$ $373\,^{\circ}C$

• A
  $273\, K$ and $373\, K$
• B
  $330\, K$ and $270\, K$
• C
  $298\, K$ and $646\, K$
• D
  $270\, K$ and $650\, K$