The correct systematic name of the compound $CH_3-O-CO-CH_2-COOH$ is:

Provide the $IUPAC$ name for the following compound:
$\begin{array}{*{20}{c}}
{\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,H\,\,\,\,\,{C_4}{H_9}} \\
{\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,|} \\
{CH_3CH_2 - C - C - CH_3} \\
{\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,|} \\
{\,\,\,\,\,\,\,\,\,CH_3\,\,\,\,CH_3}
\end{array}$

Give the $IUPAC$ name of the following compound.

Give the $IUPAC$ name of the given compound.

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

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