Which of the following $IUPAC$ name is correct for $OHC-CH_2-CH(CHO)-CH_2-CHO$?

Which of the following represents the correct $IUPAC$ name for the compounds concerned?
$(a)$ $2,2-$ Dimethylpentane or $2-$ Dimethylpentane
$(b)$ $2,4,7-$ Trimethyloctane or $2,5,7-$ Trimethyloctane
$(c)$ $2-$ Chloro$-4-$methylpentane or $4-$ Chloro$-2-$methylpentane
$(d)$ But$-3-$yn$-1-$ol or But$-4-$ol$-1-$yne

The $IUPAC$ name of the compound $C_2H_5-O-CH(CH_3)_2$ is:

The $IUPAC$ name of $CH_3-CH(OH)-CH_2-CH(CH_3)-CHO$ is:

What is the correct $IUPAC$ name of the given compound?

Which of the following has an incorrect $IUPAC$ name?