Keto-enol tautomerism is observed in which of the following?

The reaction of $C_6H_5CH=CHCHO$ with $LiAlH_4$ gives

$CH_3-CO-CH_2-COOCH_3$ $\xrightarrow[H_2O]{H^{+}} A$ $\xrightarrow{\Delta} B$ $\xrightarrow{HCN} C$. What are $B$ and $C$?

In the following compounds,the ones that give positive iodoform test are:
$(I)$ $CH_3CH_2COCH_2CH_3$
$(II)$ $CH_3CH(OH)CH_3$
$(III)$ $1$-indanone
$(IV)$ $CH_3CH_2COCH_3$
$(V)$ $PhCOPh$
$(VI)$ $PhCOCH_3$

Identify $A$ and $B$ in the given reaction sequence:
Cyclohexylidene ethyl acetate $\xrightarrow{A}$ Cyclohexylidene ethanol $\xrightarrow{MnO_2} B$

In the reaction sequence $2CH_3CHO$ $\xrightarrow{OH^{-}} A$ $\xrightarrow{\Delta} B$; the product $B$ is