The correct options are
C CH3−CH(OH)−CH2−OH
D CH3−CH(OH)−CH−CH3
The oxidation of secondary alcohols gives ketones. Thus, the oxidation of the compounds of options C and D gives ketones.
However, if the hydroxyl group is present on the terminal carbon atom (primary alcohol) then the oxidation will result in an aldehyde. Thus the compounds of options A and B on oxidation will give aldehyde.