Methyl butanoate, $\text{C}_5\text{H}_{10}\text{O}_2$, is an ester used in the food industry to add an apple flavour to products. Counting methyl butanoate itself, how many structural isomers of $\text{C}_5\text{H}_{10}\text{O}_2$ are esters?
- A6
- B8
- C9
- D10