Which of the following compounds reacts with $50\%$ sodium hydroxide solution to give the corresponding alcohol and acid?

$A$ student is given one compound among the following compounds that gives a positive test with Tollen's reagent. The compound is:

Arrange the following reagents in the correct order in which the above transformation is carried out:

$3 CH_3COCH_3 \xrightarrow{HCl} (CH_3)_2C = CH - CO - CH = C(CH_3)_2$
This product $B$ is obtained when acetone is saturated with hydrogen chloride gas. $B$ can be:

$A \xrightarrow{} (CH_3)_2C=CH-CO-CH_3$. $A$ is:

An organic compound neither reacts with neutral ferric chloride solution nor with Fehling solution. It,however,reacts with Grignard reagent and gives a positive iodoform test. The compound is: