What type of isomerism is exhibited by neopentane $(C_5H_{12})$?

Given below are two statements :
Statement $(I) :$ $CH_3CH=CHCH_3$ and $cyclobutane$ are isomeric compounds.
Statement $(II) :$ $CH_3CH_2CH_2CH_2NH_2$ and $(CH_3CH_2)_2NH$ are functional group isomers.
In the light of the above statements,choose the correct answer from the options given below :

Which of the following are meso compounds?

$Propanone$ and $propanal$ are:

The compounds $(I)$ $HOOC-CH(OH)-CH(Br)-COOCH_3$ and $(II)$ $CH_3OOC-CH(Br)-CH(OH)-COOH$ are related as:

The following compounds are: