Which of the following alkenes is the most stable?

The reaction shown below is an example of:
$Cyclohexene + Br_2 \rightarrow 1,2-dibromocyclohexane$

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 . . . . . . .

Which of the following products is not formed during the reaction: $CH_3-CH(CH_3)-CH=CH_2 \xrightarrow{Br_2/aq. NaCl}$?

$C_8H_{16}$ that can form cis-trans geometrical isomers and also has a chiral centre,is

Bromination of $(E)-2$-butenedioic acid gives: