Which of the following is a metamer of the given compound $(X)$?

How many structural isomers are possible for a compound with molecular formula $C_3H_7Cl$?

What are isomers called that have different structures and exist in equilibrium with each other?

Identify the correct statements from the following. Choose the correct answer from the options given below.
$A$. Pentan$-3-$one and Pentan$-2-$one are metamers.
$B$. Butanenitrile and Butaneisonitrile are functional isomers.
$C$. Butan$-1-$ol and Butan$-2-$ol are position isomers.
$D$. Butan$-1-$amine and $N$-methylpropan$-1-$amine are homologous.

The two compounds $CH_3CH_2CH_2OCH_3$ and $CH_3CH_2OCH_2CH_3$ are examples of which type of isomerism?

Which of the following is not an isomer of pentane?