Which of the following statements is correct?

Find the mismatched pair.

Assertion $(S)$: The measure of disorder in a biological system is called free energy.
Reason $(R)$: The energy available in a biological system to perform work is called entropy.
$(A)$ Both $S$ and $R$ are true,and $R$ is the correct explanation of $S$.
$(B)$ Both $S$ and $R$ are true,but $R$ is not the correct explanation of $S$.
$(C)$ $S$ is true and $R$ is false.
$(D)$ $S$ is false and $R$ is true.
$(E)$ Both $S$ and $R$ are false.

$A$: Water is an efficient solvent.
$R$: Polar nature is an important property of water.

Pellagra is caused by the deficiency of

$A$ deficiency of which of the following causes continuous bleeding from an injured part of the body?