Which of the following is used as a hypnotic?

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 $B$.

The major product formed in the following reaction is:

Which of the following gives the iodoform test?

In the given reaction,what will be $A$ and $B$ respectively?
$(CH_3)_2CO$ $\xrightarrow{NaCN/HCl} A$ $\xrightarrow{H_3O^+} B$