Which of the following depict the same ?
$1$ and $2$
$1$ and $3$
$2$ and $3$
$1, 2,$ and $3$
An organic compound exhibits optical isomerism when
Given : $I$ and $II$ are
Of the following, the compound possessing optical isomerism
The Fischer projection of $D$-erythrose is shown below.
(image)
$D$-Erythrose and its isomers are listed as $P , Q , R$, and $S$ in Column-$I$. Choose the correct relationship of $P , Q , R$, and $S$ with D-erythrose from Column $II$.
(image)
Among the following, the optically inactive compound is