The centigrade (${}^\circ C$) scale can be converted into kelvin scale by the formula:
a) Temperature in Kelvin + $273$
b) Temperature in Kelvin - $273$
c) Temperature in Fahrenheit + $273$
d) Temperature in Fahrenheit - $273$

Hint: There are more than two units of measurements of temperature. All of these units share a unique relation with every other unit. Among them, \[{}^\circ C\] and $K$ are the most commonly used ones.
\[{}^\circ C\] takes into consideration two fixed points while $K$ is defined in terms of one fixed point.

Complete step by step answer:
Various experiments as well as many of our day-to-day life events are affected by the temperature measurements. Be it the setting of temperature of the microwave oven or be it the prediction of the weather of the day, temperature measurements play an important role in our lives.
But there are many units in which a temperature is measured. We cannot dismiss other units stating them as redundant because every unit holds significance in certain specific scenario where other units of measurements of temperature may prove cumbersome to work with or will not at all be applicable.
Among these different measurement units of temperature are degree Celsius (\[{}^\circ C\]) and degree Kelvin ($K$).
Degree Celsius (\[{}^\circ C\]) is a scale of measurement of temperature which the whole has agreed upon, on the basis of two fixed points. These points are ice points and steam points. Ice point is defined as the point where the liquid and the solid state of water (ice) are present simultaneously. This point is agreed upon as \[0{}^\circ C\]. Steam point is the temperature at which the liquid and solid states of water are present simultaneously. This temperature is agreed upon as \[100{}^\circ C\].
Kelvin scale is defined with respect to the triple point of water. Triple point of a substance is a temperature at which all the three states of the substance, namely solid, liquid and gas, are present simultaneously. This scale is not affected by the properties of any substance. It is divided into 100 equal parts between the ice and the steam points.
There is a unique relation between every scale of measurement of temperature. The relation between Celsius (\[{}^\circ C\]) and Kelvin ($K$) is :
$K={}^\circ C+273$ -------(i)
$\Rightarrow {}^\circ C=K-273$ -------(ii)

So, the correct answer is “Option B”.

Note: The SI unit of temperature is Kelvin ($K$ ) and not Celsius (\[{}^\circ C\]). The temperature value in the Kelvin scale is always greater than the Celsius scale. This can easily be seen from equation (i), where we have to add $273$ in Celsius scale in order to equal the Kelvin scale.