Assertion:
Sugar charcoal is prepared by dehydration of cane sugar.
Reason:
Sulphuric acid acts as a dehydrating agent.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
C. Assertion is correct but Reason is incorrect.
D. Both Assertion and Reason are incorrect.

Hint: We must remember that the sugar charcoal is the purest form of amorphous carbon. It is generally formed by either distillation of cane sugar or by dehydration of sugar. To understand this, let’s study the process in brief.

Complete step by step answer:
Let's discuss the assertion first.
It states that – Sugar charcoal is prepared by dehydration of cane sugar.
This statement is true because sugar charcoal is also formed by dehydration of cane sugar.
The chemical reaction proceeds in the presence of concentrated sulphuric acid.
We can write the chemical reaction as,
${C_{12}}{H_{22}}{O_{11}}\xrightarrow{{conc.{H_2}S{O_4}}}12C + 11{H_2}O$
In this chemical reaction, concentrated sulphuric acid is important.
It acts as a dehydrating agent causing dehydration of cane sugar.
It absorbs water from the cane sugar and leaves a black carbon residue.
So, first we found that the assertion is correct. While studying the reaction we found out that concentrated sulphuric acid acts as a dehydrating reagent in the process.
Hence, both the assertion and reason are the same. Also, the reason is the correct explanation for the assertion.

So, the correct answer is Option A.

Note: We have to know that the sugar charcoal is a pure form of carbon prepared by distillation or dehydration in the presence of concentrated sulphuric acid. Sulphuric acid acts as a dehydrating agent which absorbs all the water content leaving the carbon residue behind. It is used to prepare artificial diamonds when heated strongly at high temperatures. It is also used as a reducing agent in the process of extraction of metals.