Identify $A$ in the following reaction.

$$A+\mathrm{CH}_3 \mathrm{MgBr} \xrightarrow{\text { Ether }} \text { complex }\xrightarrow{\mathrm{H}_3 \mathrm{O}^{+}}\left(\mathrm{CH}_3\right)_3 \mathrm{C}-\mathrm{OH}$$

Identify the number of donor groups present in EDTA.

Identify the enzyme $X$ in the following reaction

$\mathrm{H}_2 \mathrm{O}_2(\mathrm{aq}) \xrightarrow{x} \mathrm{H}_2 \mathrm{O}(l)+\frac{1}{2} \mathrm{O}_2(g)$

The Total number of electrons around the carbon atom of methyl free radical are