Correct answer: A. Kelvin
In fact, in Celsius scale, water boils at [tex]100^{\circ}C[/tex].
In Fahrenheit scale, this value corresponds to
[tex]T(^{\circ} F)= \frac{9}{5} (100^{\circ} C)+32 =212 ^{\circ} F [/tex]
while in Kelvin scale it corresponds to
[tex]T(K)=100^{\circ} +273.15 = 373.15 K[/tex]