The $IUPAC$ name of the given compound is:

What is the $IUPAC$ name of the following compound?

Given below are two statements:
Statement $I$: $IUPAC$ name of $HO-CH_2-(CH_2)_3-CH_2-COCH_3$ is $7-$hydroxyheptan$-2-$one.
Statement $II$: $2-$oxoheptan$-7-$ol is the correct $IUPAC$ name for above compound.
In the light of the above statements,choose the most appropriate answer from the options given below:

The $IUPAC$ name of crotonaldehyde is

Give condensed and bond line structural formulas and identify the functional group$(s)$ present,if any,for:
$(a)$ $2,2,4-$Trimethylpentane
$(b)$ $2-$Hydroxy$-1,2,3-$propanetricarboxylic acid
$(c)$ Hexanedial

What is the $IUPAC$ name of the following compound?