Answer
a) functionalized hydrocarbon - carboxylic acid
b) functionalized hydrocarbon - aldehyde
c) hydrocarbon
d) functionalized hydrocarbon - ether
Work Step by Step
a) the compound is a functionalized hydrocarbon since it contains oxygen in addition to carbon and hydrogen. It has an $-COOH$ group, so it is a carboxylic acid
b) the compound is a functionalized hydrocarbon since it contains oxygen in addition to carbon and hydrogen, it is an aldehyde ($CHO$ group)
c) the compound is a hydrocarbon
d) the compound is a functionalized hydrocarbon since it contains oxygen in addition to carbon and hydrogen. It has a general formula of $R-O-R'$ , so it is an ether