Ethyl acetoacetate shows which type of isomerism?

Compounds with the same molecular formula but differing in their structures are called structural isomers. What type of structural isomerism is shown by $CH_3-S-CH_2-CH_2-CH_3$ and $CH_3-S-CH(CH_3)_2$?

How many cyclic isomers are possible for $C_4H_6$?

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 compounds will show metamerism?

In the reaction,as shown in the image,the number of possible isomers for the organic compound $X$ is