Which of the following is the most stable alkene?

The relation between $(A)$ and $(B)$ is:

Two particles undergo $SHM$ along parallel lines with the same time period $(T)$ and equal amplitudes. At a particular instant,one particle is at its extreme position while the other is at its mean position. They move in the same direction. They will cross each other after a further time:

The bond energy of $Cl_2$,$Br_2$,and $I_2$ follows the order:

$A$ sound source is moving towards a stationary observer with $1/10$ of the speed of sound. The ratio of apparent to real frequency is

Match column-$I$ with column-$II$ and choose the correct combination from the options given below.

Column-$I$	Column-$II$
$A$. National Botanical Research Institute	$I$. Carolus Linnaeus
$B$. Indian Botanical Garden	$II$. Taxon
$C$. Binomial Nomenclature	$III$. Howrah (India)
$D$. $A$ unit of Classification	$IV$. Lucknow