Which of the following compounds will show metamerism?

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.

Which of the following can show metamerism?

How many isomers are possible for the formula $C_2BrClF_4$?

The number of structural isomers of ${C_4}{H_{10}}O$ is:

Which of the following methods of structural formula representation conventionally uses a point for the front carbon and a circle around it for the rear carbon?