Which of the following compounds has correct IUPAC name?

$C{H}_3-C{H}_2-C{H}_{2}COOC{H}_{2}C{H}_3\to$ butanal

$$\begin{gathered} C{H}_3-\underset{|}{C}H-C{H}_2-CHO \\ C{H}_3 \end{gathered}$$ 2- methyl butanal

$$\begin{gathered} C{H}_3-\underset{|}{C}H-\underset{|}{C}H-C{H}_3 \\ OH C{H}_3 \end{gathered}$$2-methyl--3-butanol