Which functional group is found in methanol ($C_1{H}_{4}O$)?

Given the following generic structure: $R-X-Y=Z$, choose the most likely identities for $X$, $Y$, and $Z$ that would result in a carbonyl functional group.

Which of the following functional groups is present in a compound with the molecular formula $C_{10}{H}_{12}{O}_2$ that is commonly known as vanillin?

PRACTICE:The following molecule contains several functional groups. Of the choices given, select the most appropriate answer (not all functional groups may be listed).