Refer to the given structure of adenylic acid. In this,identify $A$.

$A$ pyrophosphate cleavage takes place when

Statement $P$: $A$ water molecule must be added to form a complex organic substance.
Statement $Q$: $\text{Maltose} + H_2O \xrightarrow{\text{hydrolysis}} \text{Glucose} + \text{Glucose}$

What are the charges on $H$ and $O$ atoms in a water molecule, respectively?

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.

Which of the following types of water is found in the highest amount in the protoplasm?