The reaction of hydrazine $(NH_2NH_2)$ with aldehydes and ketones yields a compound with the general structure:

The product $(A)$ of the following reaction is:

The product $(C)$ of the reaction is:

$Ph-CO-CH_3 \xrightarrow[H_2O]{Mg-Hg}$ Product. The main product is:

When acetaldehyde is heated with Fehling solution,it gives a red precipitate of:

The starting material is $2,3-\text{dimethylbut-2-ene}$. It undergoes ozonolysis followed by reduction with $Zn/H_2O$ to form product $A$. Product $A$ then reacts with $CH_3MgBr$ followed by hydrolysis to form product $B$. Identify product $B$.