Write at least three structural formulas of substances corresponding to the composition of С5Н10О2

Write at least three structural formulas of substances corresponding to the composition of С5Н10О2 and belonging to at least two classes of substances.

Substances that have the same quantitative and qualitative composition, but differ in the structure of the molecule, and therefore in their properties, are called isomers. Isomers can differ in the structure of the carbon skeleton or belong to different classes. So substances with a composition – С5Н10О2 – can be acids, or they can be esters.
CH3 – CH2 – CH2 – CH2 – COOH – pentanoic acid;
CH3 – CH2 – CH (CH3) – COOH – 2-methyl butanoic acid;
CH3 – CH2 – CH2 – COO – CH3 – butane methyl ether.