Which alkene is formed from the following pair of alkylidene phosphorane and carbonyl compound?

$CH_2=CH_2 \xrightarrow{Br_2/H_2O} A$. In the above reaction,the compound $A$ is:

$CH_3-C(CH_3)=CH-CH_3 \xrightarrow[KMnO_4/\Delta]{NaIO_4}$ Product will be

The $IUPAC$ names of some alkenes are given below. Determine the correct stability order: $A$. $2$-Methylbut-$2$-ene, $B$. $cis$-But-$2$-ene, $C$. $2,3$-Dimethylbut-$2$-ene, $D$. Prop-$1$-ene.

Molar mass of the hydrocarbon $(X)$ which on ozonolysis consumes one mole of $O_3$ per mole of $(X)$ and gives one mole each of ethanal and propanone is $...... g\ mol^{-1}$ (Molar mass of $C: 12\ g\ mol^{-1}, H: 1\ g\ mol^{-1}$)

Consider compounds $A$, $B$, and $C$ with the following structural formulae:
$A = CH_3 - CH_2 - CH_2 - CH_2 - CH_2 - OH$
$B = CH_2 = CH - CH_2 - CH_2 - CH_3$
$C = HO - CH_2 - CH_2 - CH(OH) - CH_3$
For the conversion of $B$ from $A$, the reagent $(D)$ required is . . . . . . and the structural formula of the product $(E)$ obtained when $C$ undergoes the same reaction using excess reagent $(D)$ is . . . . . . .